As a current DL student at Bristol, I thought I'd share my experiences.
Prior to enrolling on the course, the general advice I was given was to learn the question bank, there was far too much information to retain and it wasn't always obvious which parts would be most relevant. When I recieved the study material I found that they had changed the way the course runs and now they'll only sign your exam application when you've completed every lesson (approx 140 of them) and gained satisfactory results in the progress tests.
I was disheartened at first but I've enjoyed the course the way it's structured, the learning experience was relaxed and at a manageable pace. I have a much better understanding of the concepts, how they all fit together, and am using this theoretical knowledge every day in my hour building. My flying, and confidence has improved vastly as a result.
I've completed the course and have started to focus on the question bank, with quite pleasing results. The only downside to distance learning, in my opinion, is the lack of support, or should I say the time taken to resolve queries. There's a good forum and my questions have always been answered, but I'm a bit impatient, if there's something I want to know, I want to know it NOW! But don't take that as a negative, the more effort you have to put in to truly understand something, the more likely it is to "stick".
I've just had confirmation from the CAA of my exam dates in December, so I'll probably be able to give you a better idea then, if DL is a good idea!
Good luck in whichever route you decide to take.
