I've just spotted that the Museum of Naval Firepower is disposing of quite a number of their items. A link to the PDF with the details on can be found here:
https://www.museumsassociation.org/d...c-70106faaeaf1

No idea if you'll be able to wrangle some of the items out of them, or if they'll restrict to museums and charitable trusts (some museums will consider private individuals after all other options have been exhausted), but it can't hurt to try if there's something that catches your eye.