Thermoman, I'm looking into these sorts of things just now and concluded that ATPL theory is the Way To Do It, even if I'm only planning on doing the CPL flying short term. Check LASORS for the reason why: ATPL exams are good for CPL and IR flying, but not the other way round - if you do just the CPL and later decide to get the (f)ATPL you have to sit them all again. Instructors I've asked at my club agree.
As for the distance learning options, do shop around. I've heard good things about Bristol, though there are plenty of Cranfield-based shops which are a lot more convenient for me. (Speaking of which, I'm attending Cabair's prospective-trainee seminar at Cranfield this Saturday to hear what they have to say and get something approximating serious figures out of them, though I imagine they'll be focussing on integrated ab initio students.)