Thanks so much for all your help.
The cavalry came in the shape of Marvell, and a lengthy discussion yesterday about IP addresses resolving to locations and using a 'lite' database to cross check and do a sort of 'country indicator score' system.
I'll be adding the new code—PLUS the new website soon.
Again, thanks for all your help, but Marvell gets the bounty.
(Well, he will do when he sorts his greylists out

)