I took Scott Dorsey's recommendation elsewhere and bit on an Adcom amp
to power a pair of passive Reveals (which are 6 ohm according to
Tannoy's site BTW) and just want to say it worked out great, thanks
Scott! Of course the caveat is that the Adcom's have unbalanced
inputs, but this works fine in my case.

I actually ended up buying two different amps: a GFA-535mkII (2X 60W
into 8 ohms or 100W into 4 ohms) and a current production GFA-5400 (2X
125W into 8 ohms or 200W into 4 ohms). Both sound great but the bass
response is noticeably better at any given volume with the 5400,
supporting the "big amps are better for passive Reveals" theory stated
elsewhere...

The 5400 is a laid back, smooth sounding amp (sig path is 100%
mosfets, class A discrete in front, and power runs class A up to 25
watts then goes AB from what I've read) with tight full bass, which
seems a nice match for the Reveals...