Hi DB,
I found the distance learning very hard work. You have to apply yourself and being a police officer (shift work etc) does not help. However, it is achievable, I am evidence of that!! I used Bristol Ground School and can't speak highly enough of Alex and the team he has there.
What made things that little bit more difficult for me was the fact I was in Bermuda while I was studying. Sometimes, no matter how you read the text in front of you, there me be something which just doesn't sink into the grey matter. If I was in the UK when I was studying, it may have been easier to have made a phone call to BGS and have a chat with someone who may have been able to "spoon feed" me. Obviously, time differance, expense etc, this wasn't an option I was able to use. You however, do have that option.
However, the BGS forum was helpful, as were the two week crammers. There were plenty of "a ha, so that's how it works" moments once I was in the classroom. Several mates of mine have also completed the studies full time. The one thing we all agree on is that the subject matter isn't overly difficult to understand. It's just that there's an awful lot to remember. The marks I scored were similar to the marks of my mates who studied full time. It just took me a little longer to get there, which, had a plus side. I was able to save money to help fund the training!!
I didn't leave the Bermuda Police Service until I was through the ATPL exams and ready to hourbuild and train full time. My advice to you would be to do the same. It's a little bit more time consuming, but like I said, at least you'll have an income when you're studying, and can take the career break once you're ready to train full time. That's certainly what has worked for me.
Good luck!
Dmk