Just been looking at the 1988 firearms(amendment) act as discribed in Tony Jeeves book 'a collectors guide to collecting deactivated weapons',and it would seem,in the UK,that strict methods of de act work as laid down by the home office have to be checked at either the Birmingham proof house or the London proof house where,if all is well, a individual certificate of de act is issued and signed by the proof master.
So it would seem without this certificate or the proof house stamps on key parts of the weapon(crossed swords,DA & date numbers on Birminham proof house and scimitar,DA & date numbers on the London proof house) that they are not legal de-acts in this country,we are in the E.U.,but every country has it's own laws.(I think it is daft that I need a passport to go to France but don't need it again in Europe once there!!!)
Very handy book to have if a collector,not only explains the law and de-acts but also gives great detail of the work,to home office standard,carried out on all types of weapons
Cheers
Tony