DJ knows his stuff. I bought a bike off him in 2011 and it was the best set-up new bike I have ever had. I didn't have to alter, tighten, adjust or trim anything (and I did check). All the cables were the right length and gears indexed perfectly.
When the frame cracked in 2016 he handled the warranty claim without any hesitation even though it was a money loser for him because although the manufacturer supplies the frame and any major components required to rebuild the bike (not a straight swap due to frame availability) the workshop time and small consumables like cables and things comes out of his pocket.