Hi - Mark Watson at Bestf.net told me this:
The UK mail order source is a guy called Ken Slater, whose been active in SF fandom for decades. Basically he gets a wodge of mags flown in from the states, and distributes them by mail. He charges very little on top of the cover price.
I contacted Ken to ask if he had a spare of the double July/August Issue of Analog. This was his reply:
Yes, can do. £4.50 post paid - cheque, credit card, or PayPal. I mailed those out 2nd May. - the October issue was mailed out 24 July; £3.15 post paid.being a "single" issue. Works out more expensive than news-stand copies, but I have them sent in by air freight from the US. Which is no longer so cheap as once it was.
Regards
Ken
So there you are, problem solved - at least for now. Dennis