Are we missing something here? "Exempt BP revolver". Is this one exempt under the handgun ban or exempt as an antique?
If it is a repro then the police will have taken the spare cylinder. They should not have done it with an original. If they have the answer would have been to take it "Off-Ticket" and keep it just as a curio.
What is stupid is the fact that you can have two revolvers the same caliber...but not a spare cylinder!
I have heard of people buying a commemorative boxed set (repro) BP revolver that had a spare cylinder and it was allowed here because of it being a collectable item!
There is no consistency in the way the the rules are administered.