I think (and I really could be wrong here) that generally the UK versions of all the FF series are actually called international editions, they tend to be either a direct translation of the Japanese original or have a few extra's thrown in that the US market dont have (Dark Aeons in FFX for example). As far as I know, there is no difference between the US and UK versions of VII, there was an 'extended' Japanese version which added nothing to the story but had an encyclopedia-type extra. As I say, I can't verify this, its just what I have picked up over the last few years.

There is no actual difference between the 2, i have a UK version of the game and a US game guide completed the game to the max with the guide, nothing was out of place or different

I replied to this before, but it apparently died in the hacking.
In any case, no, the International editions are the Japanese re-releases, often with additional content and in the case of the newer ones, English Voice Acting. FF7 International is what you're thinking of when you refer to the encyclopedia type extra. It had a 4th disc with all sorts of info on it. Like a key item Gallery (with the text of Zack's letter, and an Image of Tifa's stretched Undies- Pink and Frilly, BTW- among them).