To clarify a little, there were three 'Cromwells' on BoB. Dennis Roberts' Centaur, originally restored by Colin Jones using a dozer hull and a range turret and two Finish Charioteers. These were less convincing as they retained many of the Charioteer parts, one still used the Charioteer turret ring making it look a little odd. This is not a criticism, they were modded for a film and time is always tight on such projects.
One of these ended up in the Czech Republic and the other is currently being prepared for a move to Brussels as part of an exchange.
There are only two genuine, unmodified Cromwells in the UK, Bovingtons and the Wheatcroft Collections. The latter is a German range wreck and I have no idea when Bovingtons last ran. It is complete though.
Charioteers were of course Cromwells originally and retained the Cromwell makers plate inside so they do count! There are about half a dozen Charioteers in the UK, though I don't think many will be converted back to Cromwells. It is a big job to do properly and the parts are not easy to find.....
A&E 2012? Unlikely and not just for the reason of their size! A troop at full chat would be good though....