Bill, I am but a mere American, and speaking in total ignorance of what's involved in shipping airguns to the UK from Germany.

But assuming that hurdle can be surmounted, the richest source for model 27's that I know of is the German auction site "eGun." There are usually several nice ones on offer there at any given moment, plus they usually go for very reasonable money. I got quite a few airguns from there, before DHL and the German post office decided that shipping airguns to the USA was some form of unbearable evil.

Good luck in your search.