I know a lot of people on here are interested in minting coins or medallions so hopefully someone can answer this . . .

I'd like to design & strike a coin commemorating the birth of my favourite niece's son and after proofing it in cheap metal I'd like to do it in 22ct Gold. I know of a small manufacturing jeweller who could help here but to keep costs to a minimum would it be possible & legal to re-strike an existing coin???