I understand that Proof Regulation only relate to sale or the offer for sale. It may be wise to check with the Proof House first for their advice. This is how I interpret it so it might need expert clarification. Reading the Act it says: 'The Proof Acts lay down that no small arm may be sold, exchanged or exported, exposed or kept for sale or exchange or pawned unless and until it has been fully proved and duly marked'. Giving it away is not mentioned. Reading further I may be wrong about its current proof status as it says: 'Arms previously proved and bearing apparently valid proof marks are deemed unproved if the barrels have been enlarged in the bore beyond certain defined limits or if the barrel or action has been materially weakened in other respect'. I think the key words here are 'materially weakened' and how that can be interpreted.
As I say, it is best to check with the Proof House on this one. You will certainly not be allowed to Export it according to the above even as a gift. Remember it will still be classified as a firearm and subject to the rules and regulations as regards shotguns.
I will p.m. you with my home phone number as I have another thing to ask you about your auction experiences. Lagopus.....