Thanks for the endorsement Rae.
Redrex, if you haven't come across it yet, my T2K website is here:
http://www.twilight2000files.com/
Whilst not exclusively devoted to the UK, there is, as Rae said, a fair collection of UK material including my own Alternative Survivor's Guide to the UK.
If you're looking for something on Cornwall I'd suggest looking here
http://www.twilight2000files.com/page38.html
http://www.twilight2000files.com/page71.html
http://www.twilight2000files.com/page84.html
If you're looking for more general stuff I'd suggest starting here
http://www.twilight2000files.com/article01.html
Or here
http://www.twilight2000files.com/page30.html
and navigating your way through the various sections:
If you look for the parts in boxed text in particular, they are generally intended to be adventure "seeds".
Bear in mind much of it differs from the published version
Hope that helps.