@QuincyJones
To answer your OP, I can import a fully functional, plug/play Model M for approximately $70 shipped, $60 if in bulk. All this is $CAD. The price of the keyboard itself is low, but the margins when sold on my end aren't high enough for me to make this a routine import. I only stock 5 or so IBM keyboards at maximum, since I don't have a dedicated warehouse for merchandise.
So, if you're still set on getting a Model M, here's what I can do. I'll purchase the keyboard with the assurance that you will pay the full cost to me, and it will be shipped directly from source to you, so I don't have to cover shipping from my locale to Britain, the shipping cost being the main stumbling block whenever I make a sale. I imagine that this cannot cost more than £50 when it reaches you, and £50 would be, according to what appears from your posts, a reasonably price for a functional Model M in good condition. 1390131 and 1390120 are out of the question, though.