In June 2014 I ordered the Big Y test from Family Tree DNA. The results identify my terminal SNP as R-L159.2, which is downstream of R-L21 and R-Z255.
Additionally the Big Y discovered multiple downstream (more recent) novel variants. Among these is the newly discovered SNP R-Z16434.
A total of nine Big Y kits are known to share this marker. These results can be viewed at Alex Williamson's R-L21: The Big Tree. http://www.littlescottishcluster.com/RL21/NGS/R-Z255.html
Of the nine kits, two men trace their families to England, five to Ireland, one to Sweden and one to Norway.
Based on my Z16434 result, I have encouraged several of my DNA matches at Family Tree DNA to test for this SNP. To date seven of these men, including four lineage 1 Deaton project members, have tested positive for Z16434.
If you are are a member of lineage 1 and have not yet tested for this new SNP, I encourage you to do so. The test can be ordered from FTDNA from the Advanced Tests section on your yDNA upgrade page.
Additional information about the Big Y test is located here: https://www.familytreedna.com/learn/y-dna-testing/big-y/