IMO there were two routes to the Isles.
One by the maritime route from Anatolia via Crete, Thessaly, Balkens, Italy, Pillars of Hercules (or overland via Garonne), Tartessos, Galicia, Morbihan, Isles.
One by the river route from Anatolia, Balkens, Danube, Rhine, Rhone, Loire, Meuse, Seine, Morbihan, Isles.
The maritime migration was the first with the first wave from Anatolia to Crete. I don't think the migration was in one direction. It took one sailing season to go from The Black Sea to the Pillars of Hercules and back using the anti clockwise currents of the Meditteranean. The return trip was via the North African Coast.
The Phoeniciens followed this route later and had exchanges with the Celts at Tartessos.
A major hub in the Atlantic Facade was Morbihan especially for communication between the Atlantic, The Isles and Iron Age Halstatt and Le Tene, connecting P312 to U106 and L21 to U152, and it was a major hub in the Atlantic, Megalithic, Copper and Bronze Ages. So P312 and L21 went via the Atlantic route and U106 and U152 via the River route.
However if you look at the coastal migration path from Anatolia the major hubs on the Iberian coast were Tartessian including Huevla and Rio Tinto for copper mining, Tagus and Galicia. Much of the recent research and publications including Cunliffe & Koch, Moffat & Wilson and Klyosov also agree with this route.
I created a strawman which attempts to explain the Atlantic route. http://m.box.com/view_shared/d0nr7768zv18ht6tk28ihttps://www.box.net/shared/pf653l1r181ry7r61ix4
One of the major conferences on the subject was "Celtic from the West". The contributions of Cunliffe, Koch, McEvoy and Bradley are particularly interesting.
Here are some of the highlights:
Part 1. Archealogy
Celtization from the West,
the contribution of architecture.
Fig 1.1 Relative density of ancient ‘Celtic looking’ place names. Hot spots on the atlantic Façade including Iberia..
Fig 1.3 Greek knowledge of the Celts in the age of Hecataeus and Herodotus. Largely confined to the Mediterranean and Black Sea. Greeks and Romans are not a reliable source for commentary on the Isles as much of their knowledge was second hand.
Fig 1.4 A cognitive geography of the Atlantic Zone as it might have been viewed by an Atlantic mariner, showing major rivers and inlets of Iberia and France.
Fig 1.5 Enclave colonisation. Europe in the period c 5500 - 4100 showing the two principal routes by which the Neolithic way of life spread through Europe from the southern Balkans, the overland spread via the Danube and North European Plain and the Mediterranean route by sea ultimately to the Atlantic coast of Iberia.
Fig 1.6 The distribution of megalithic tombs shows them to be essentially an Atlantic phenomenon. The earliest tombs - passage graves dating c 4,500 - 3,500 BC - have a maritime distribution, suggesting that the beliefs and the technologies behind the construction was along the Atlantic seaways.
Fig 1.7 The distribution of jadeite axes from their source in the Western Alps across Europe. The distribution vividly displays the exchange networks then in operation.
Fig 1.8 The distribution of Maritime Bell Beaker in Atlantic Europe during the 3rd Millennium, the crucial nodes in this network were the Tagus estuary and the Morbihan, while major hinterland routes followed the navigable rivers. The map indicates the initial movements were maritime. Trade routes with Ireland and Southern Britain for copper and tin.
Fig 1.9 The extent of the Bell Beaker complex 2700-2200 BC. Major corridors of communication by sea and river. Mediterranean, Atlantic, Danube, Rhine,
Fig 1.10 The interaction of the Corded Ware and Bell Beaker Complexes c2500 BC. North European Plain.
The Celts from everywhere and nowhere. Raiumund Karl.
Different origins of Celtic cultural features with Linguistic Celtic origin along the Atlantic Façade, Archaeological ‘La Tene’ origin in central Europe and Historic ‘Druidic’ origin in the Isles.
Newly discovered inscriptions from the south-west of the Iberian peninsula. Tartessian. Amilcar Guerra.
An analysis of about 50 newly discovered stelae fromTartessian. Several photographs and sketches.
Part 2: Genetics.
A genetic impression of Britain in Atlantic Europe. Ellen C. Royrvik.
Analysis of MC1R ‘red hair’ frequencies.
Map of Genetic variation in Europe.
Fig. 4.6 shows a Gaulish expansion leading to Iberia, Western France and the Isles.
Fig 4.7 shows a rough Highland and Lowland divide of the Isles with the south east more La Tene Gaulish and the West including Ireland representing a more pan Celtic profile.
Irish Genetics and the Celts. Brian McEvoy and Daniel Bradley.
Fig 5.1 Genetic contour map of Europe showing contours from Anatolia (SE) to the Isles (NW).
Fig 5.2 Genetic map of the Isles calculated from 300,000 SNPs spread across the autosomal genome showing Ireland, Wales, Scotland and England.
Fig 5.3 Contour map showing the geographic frequency distribution of the Irish Modal Haplogroup (IMH) and closely related Y-chromosones showing the NW Ireland hot spots.
Fig 5.4 Illustrative Genealogy of the Ui Neill dynasty (and derived surnames) from the 5th C to the present day. Future testing will provide further insights as well as generating fresh debate on the Irish past.
A reanalysis of multiple prehistoric immigrations to Britain and Ireland aimed at identifying the Celtic contributions. Stephen Oppenheimer.
Fig 6.1 Map of Europe with frequency of ancient place names which were Celtic with hotspots in NW France, Iberia and the Isles.
Fig 6.2 Frequency distribution of genetic Haplogroup R1b. The densest gene flow follows the Atlantic façade, thus favouring Ireland which was then part of the continent.
Fig 6.3 Frequency distribution of genetic haplogroups Irb2 (M26) and Irb* (P37.2). The hotspots and possible homeland of Irb in the Balkens with Irb2 further to the West.
Fig 6.4 Frequency distribution of genetic haplogroup J2 (M12) in Europe showing expansion from the Balkens and hot spots in SE and NW Iberia. (Cruciani)
Fig 6.5 Frequency distribution of genetic haplogroup E3b1a2 in Europe with expansion from the Balkens. Cruciani.
Fig 6.6 Principal Componants Ananysis of Y Chromosones in Western Europe using R1b and R1a1 and I1b2 and I1a showing a gradient from Ireland via the Isles, Continent to Scandanavia.
Part 3 Language and Literature
Origen of the Celtic Languages. G.R. Isaac.
An analysis of the Indo European languages.
Tracking the course of the savage tongue. David N. Parsons.
Fig 8.1 British River names.
Fig 8.2-8.5 Various maps of ancient Europe showing occurrence of ‘~briga’, ‘~duno’, ‘~duro’,’~mag’ names. Many in Iberia.
Paradigm Shift? Interpreting Tartessian as Celtic. John T. Koch.
Fig 9.1 The Late Bronze Age and Early Iron Age in the south-western Iberian Peninsula: ‘warrior’ stelae, Phoenician colonies, and Tartessian inscriptions. Shows Keltoi Tartessos region.
Fig 9.1 Celtic Expansion from Halstatt/La Tele central Europe.
Fig 9.3 The Ancient Celtic Languages. Shows Halstatt, Early La Tene, Urnfield and Atlantic Bronze Age with sharp division of Goidelic, Brittonic and gaulish.
Tartessian Inscriptions: There follows over 70 detailed photographs and transcriptions of stelae many of them with depictions of warriors and their their epitaphs.
“Where the evidence of Tartessos and Tartessian changes the picture is in showing that one of the most dynamic regions influencing Ireland and Britain during the period c 1300 – c900 BC was probably itself Celtic speaking and also in contact with and receiving influences from non Indo European partners in the eastern Meditteranean and north Africa.
Tartessian Linguistic Elements: A detailed alphabet and index of names and analysis of the grammar follows.
Ancient References to Tartessos. A very interesting compendium of classical references to Tartessos from Greeks, Romans, Assyrians and Hebrews, ranging from Aristotle,Cicero, Hecataeus, Herodotus, Livy, Ovid, Pliny the Elder, Seneca, Strabo, Theopompus and biblical references from Genesis, Kings, Chronicles, Psalm, Jeremiah, Jonah.
The Problem of Lusitanian. Dagmar S. Wodtko.
The core region inhabited by Lusitanian’s seems to have comprised the lands between the Douro and Tejo in northern Portugal.
Celtic from the West
Cunliffe & Koch
This book is an exploration of the new idea that the Celtic languages originated in the Atlantic Zone during the Bronze Age, approached from various perspectives: pro and con, archaeology, genetics, and philology. This 'Celtic Atlantic Bronze Age' theory represents a major departure from the long-established, but increasingly problematic scenario in which the story of the Ancient Celtic languages and that of peoples called Keltoi 'Celts' are closely bound up with the archaeology of the Hallstatt and La Tene cultures of Iron Age west-central Europe. The 'Celtic from the West' proposal was first presented in Barry Cunliffe's Facing the Ocean (2001) and has subsequently found resonance amongst geneticists. It provoked controversy on the part of some linguists, though is significantly in accord with John Koch's findings in Tartessian (2009). The present collection is intended to pursue the question further in order to determine whether this earlier and more westerly starting point might now be developed as a more robust foundation for Celtic studies. As well as having this specific aim, a more general purpose of Celtic from the West is to bring to an English-language readership some of the rapidly unfolding and too often neglected evidence of the pre-Roman peoples and languages of the western Iberian Peninsula. Celtic from the West is an outgrowth of a multidisciplinary conference held at the National Library of Wales in Aberystwyth in December 2008. In addition to 11 chapters, the book includes 45 distribution maps and a further 80 illustrations. The conference and collaborative volume mark the launch of a multi-year research initiative undertaken by the University of Wales Centre for Advanced Welsh and Celtic Studies CAWCS]: Ancient Britain and the Atlantic Zone ABrAZo]. Contributors: (Archaeology) Barry Cunliffe; Raimund Karl; Amilcar Guerra; (Genetics) Brian McEvoy & Daniel Bradley; Stephen Oppenheimer; Ellen Rrvik; (Language & Literature) Graham Isaac; David Parsons; John T. Koch; Philip Freeman; Dagmar S. Wodtko.
The Scots, A Genetic Journey
Moffat & Wilson
“Now it appears that S145 (L21) also travelled along these (Atlantic) trading routes. The marker probably originated in southern France or northern Iberia and people carrying it came to Ireland and western Scotland. This was not a wave of migration but a series of small movements over time, probably in the millennium between 2,500 BC and 1,500 BC”.
R1a and R1b history:
Anatole Klyosov http://www.turkicworld.org/turkic/60_Genetics/Klyosov2010DNK-GenealogyEn.htm
The part that I found interesting was the following extract which concords with the recent Moffat and Wilson book, "The Scots, A Genetic Journey" and Cunliffe and Koch, "Celtic from the West".
"From the Anatolia, which the carriers of R1b1b2, together with their agglutinative language, reached 6,000 ± 800 years ago (Klyosov, 2008a, b), they continued moving westward toward Europe by two routes. One route went through the Balkans, where the haplogroup R1b1b2 is recorded at about 4,000 years ago (a formal calculation gives 4050 ± 890 years ago). In Sardinia, it dates from the 5,025 ± 630 years ago, Sicily 4,550 ± 1020 years ago, in Italy 4,125 ± 500 years ago, in Slovenia 4,250 ± 600 years ago. Another route went through the Middle East (the common ancestor of the modern carriers of the haplogroup R1b1b2 in Lebanon dates back to 5,300 ± 700 years ago, among the modern Jews 5,150 ± 620 years ago), then on across the North Africa (Algerian Berbers 3,875 ± 670 years ago) to the Atlantic Ocean and on to the Iberian Peninsula (3,750 ± 380 years ago), and further on to Europe (Klyosov, 2009a).
It is very likely that carriers of R1b1b2 reached Iberia 4,800-4,500 years before present, but then they had passed a “population bottleneck”, and reappeared again (through a few survived DNA-lineages) 3,750 ± 380 years ago. This is when a common ancestor of the present-day Basques lived.
Approximately 3,600 years ago that haplogroup is noted in the British Isles. This is the movement of Beaker culture - from the Iberian Peninsula in the British Isles and on the European continent. They are the ancestors of the Proto-Celtics and Proto-Italics, and, probably, Proto-Picts and other “Proto”-R1b1b2 peoples in Europe