Edmunds is based in the US and we have over 500 models on sale in this country to keep track of. The site runs largely on ad revenues and I guess the numbers don't pencil out (yet) to offer TMV and our other tools to our good neighbors in Canada or Mexico at this point, or points beyond. Plus it's hard to review cars that you don't have easy access to.
Edmunds has Forums discussions that touch on the Canadian, Chinese, Australian, European and Mexican markets and you are welcome to start one for the UK or wherever you are located or search for a discussion that may cover your interests. Our Forums members log in from all over the world.
Try the Smart Shopper or Automotive News & Views boards for general talk, or just jump into the Corolla discussions and brag about what we can't get. :-)