I have just visited Cass Business School and felt it was a great place to study finance. The building and the facilities are new and very well equiped and the location is the best.
For MBA, I think Cranfield is much better than other schools. according to rangking list of The Economist and some local people who know the field. in fact, Cranfield is the second, just after LBS. The reason why it's not being known very well is that it's not a kind of general university. it ofer only Mster course ( I suppose Phd as well but not sure)