I'll third the Art Audio recommendations having owned the 6 wpc PX-25 and auditioned a Jota w/ my ~95dB Cain & Cain IM-Bens. I also ran the PX-25 into some 90db/4ohm monitors without any problems.
Art Audio amps have over-spec'd power supplies and output transformers to supply current far beyond what their wattage ratings would imply. I mean, their power supplies can continue to deliver the full power rating(w/o sagging) much longer than most other similarly rated amps. (if I remember correctly how Joe Fratus, AA owner, described it to me)
Call Joe at Art Audio and ask him about the Kensington/Jota pairing, good chance he has tried his amps w/ Tannoys before. And Joe is dead honest about what will work, and what will not. I think he said he has run Quad 63's w/ the Jota HC before. Wasn't playing loudly, but they were able to play for hours without burning up.