Of course, 'most' is a sticky concept. In a way it has to be a matter of mood. If one feels late-Victorian-gothic-redbrick-ish, then Kelvingrove is, indeed a good contender. If one feels Between-Wars Art Deco, then maybe Broadcasting House, or Memorial Court in Clare College, Cambridge; if C17, same college's Old Court, or St Paul's; if Tudor-ish, the the Cloister Court in Queens', or if Gothic, King's Chapel is an obvious. {Oxonians will obviously produce their own, rival, list}. If it's Art Nouveau time, maybe Selfridges?

And have we, after all these years, ever outdone Stonehenge? ~~ which would probably be my #1 contender...

But may well be back with some more suggestions after a bit more thought & recollection.

≈Michael≈