Well, that's part of the thing with the Time Lords- it is the main complaint the Doctor has with them; they have all this power but their cardinal rule is to never use it. They nbever leave Gallifrey.
(There are, of course, rare occasions when the Time Lords DO get involved, but these ar eall specific plot points around stories).
The point at which the Time Lords set up their rule of non-interference is after they once tried to help the historical development of a race, and that race then destroyed itself prematurely with advanced weapons.
Fair enough, but the Doctor does not see that as justification for letting evil races go unfought.
And indeed, in a very rare event, it was the Time Lords who sent the 4th Doctor back to the point of creation of the Daleks to see if he could do anything about them- to either avert their creation or affect their development. The creator of the new Doctor Who says that he sees this as having been the first move in the Time War.
As they have not given much info about the Time War, we don't know when (relatively) it picked up again (that story, Genesis of the Daleks, having been from the 70s) and why and how, but do be sure, that was a VERY rare event for the Time Lords to become involved.
There is also this hazy notion that the Time Lords do not mind the Doctor meddling on Earth- indeed, at his first trial (he got off the second on a technicality) he pleaded that his work needed to be done, and the Time Lords considered this and said ok, but ONLY on Earth and ONLY in one time, which led to the following series of stories (the first few stories of the Third Doctor) being set entirely on Earth, helping UNIT fight aliens. That punishment was later lifted after the Doctor did the Time Lords a favour, but they clearly never liked him running around and doing stuff, except on Earth.
As to why they always come from England... it must be fate. Same reason aliens keep attacking England- stupid of them really, as that's where the Doctor always is. Even the American and Australian companions over time hgave been english people doing accents- however, Captain Jack is a genuine Yank, and the series has had a story in the States (first time ever, I believe) so we shall see if things change.
Now... as to why the Doctor, as a time traveller, cannot go back to a time to when his people were alive- just as he demonstrates to Rose in the second story, showing her the end of the Earth and then going back again, we don't know. The suggestion is that the Time Lords have been erased from time itself.