Hello Matt,
I am have been reading the posts regarding your Krieghoff Luger in an attempt to possibly save it from distruction by the British authorities.
I would suggest that you keep quiet until you are absolutely sure what steps you must follow. In other words, do not tell anybody in the UK that you have this pistol until you receive the best advice.
For your information, I have good knowledge regarding export and import regulations in various countries in Europe and the US, and my advice to you is to sell the pistol to a collector or dealer outside of the UK. Unfortunately, it would be very difficult to import the pistol into the US because it is classified as a military pistol (in the US) and it can only be imported by a licensed importer (who would need to stamp the pistol with his dealer address which is a sin) and this limitation would make matters complicated and difficult. It would be easier for you if the pistol goes to a buyer in Europe where it is rather easy to import firearms.
Another possibility is to sell the pistol through a British auction house who might be able to 'legalize' the pistol and give you the proceeds from the sale. Auction houses take a nice chunk of money from any sale, therefore, you would receive about 30%-40% less.
If you would like to receive more advice from me, you can e-mail me at
imperialarms@att.net.
Good luck,
Albert