"From looking around, the 30.5 seems a little rounder than the .8 with the 25 being the warmest of the three. Hopefully, someone's tried one or more of them with some tannoy Stirlings or Turnberrys (Turnberries?) and can weigh in."
I can weigh in. I had a Pass XA-30.5 and Pass XP-10 with Turnberry SEs. It was not a great combination. Not very dynamic. Much better results (with Turnberry) using an MC-275, Yamaha AS1200, and Benchmark HPA4/AHB2 (amp in use now). Maybe there was something wrong with my Pass amp. But I sold it to an audio engineer at Apple and didn't hear back that he was unhappy with it. Don't know what speakers he was using .....