Bingowings said:

There are vectors that can produce confusing IP information.

My external IP reads that I'm posting in Glasgow because my provider's server is there and I could share my internal IP address with a lot of different homes and presumably businesses too because of the way the paths are allocated. The IP is also registered in Amsterdam to a Berkshire company.

I've noticed that too: when I get to a page that has one of those ads that read "congratulations! you're the winner for today in [name of town]" they never get the place right! It's always a city in the general area, but never the right one. I deduced that whatever system is being used to trace my IP is far from precise.

EDIT out of curiosity, I've just tried two different methods to determine my location, and they both got it wrong. XD