I have the Definition D500 and really like them a lot. But I've never heard vintage Tannoy's. Also the D500 uses the 8" concentric which of course there's no corresponding vintage equivalent.
Right now my listening area is actually way too small for these speakers. I'm planning on an addition to my house and then I'll have plenty of room! I had to toe them in quite a bit because on axis they were way too bright.
Anyway, I would guess that the current Tannoy's have more extended highs than vintage. I' remember seen comments that the old Tannoys start rolling off at around 12k (but don't quote me on that, I could be way off).
I good place to check for Tannoy info is the group on Yahoo:
http://groups.yahoo.com/group/tannoy/