I agree with Chris' evaluation on these three bikes. My cases take me to England from time to time, and I have had a chance to try out the Mercian and the Thorn -- and bought an Atlantis from Peter White. (Who, I might add, was kind enough to steer me to a marvelous TA Zephyer triple crank in place of the Shimano I had planned on using.) No question in my mind that the Atlantis (and the Ramboulliet that I later bought from Peter as well) represent outstanding build quality and paint finish/lugs in a current product. Grant did a great job not only in design, but also in finding a perfect source to build and paint.
By the way, and contrary to what has been posted at some of the dealers sites and at Rivendell, you CAN use STI levers and a DA triple front/rear der with the Atlantis using the TA cranks. While not as 'period' as barends (which most people use) or DTs, and while I may be pilloried for saying this, the integrated levers are very smooth and fit what I wanted in these bikes, comfort, utility, ease of use.
Thanks Grant. I owe you for these bikes. (Now where the )(*(&*&^% is my Rivendell Custom?)