There's a crapload of them in England that you'll never get to fight. There are also quite a few in Canada, that you'll also never see. The UK's weakness is that they've got stuff on 5 different continents => their european base of operations, canada, australia, india and africa (which they almost never expand so that's probably not important). Their biggest army is probably in India, but it's still less than 50% of their total military score most of the time. As I said, the real problem, once you beat the british around for a bit, will be getting enough warscore, since India is a colony and colonies award much less warscore. But if you get a respectable battle bonus (with the UK you probably won't 25% unless you drag it out) and some parts of india, you can probably enforce your demands. It's just that their military score is skyhigh and you need to do enough damage for them to 'realise' that they can't win, which is harder to do than you may think.