mikl said:London is a backwater, not even a part of the great kingdom of Scotland.
It'll be less important than in vanilla, but historically London was not a capital for the sake of having a capital, like Madrid or Brasilia; rather, it was already England's most important city before becoming the established capital. It's ideally placed to control trade between the British Isles and the continent, so it wouldn't have been a backwater by any means, even without the British Empire. In fact, you could go as far as saying that the Hansa only deserve their COT in Flanders if they have good trade access to southern England. That could be the case if the powers in England decide to let the Hansa take all the profits from trade, but the only way for the Hansa to be safe is to control a port like London or Dover.