You're right civil aviation, I completely understand why they're charging upfront. If you offer a really good deal and invest resources and time and some time waster doesn't show then you're out of pocket.
For what it's worth, OBA are the only school in the US whose email correspondence is on the ball. I've mailed others a few times and received nothing or very little in the way of help! From that, and from talking to other experienced members on this forum (many thanks) I've totally decided to go with them this November.
I've planned 4 weeks and really hope to get it all signed sealed and delivered in that time. I've read that November is a pretty quiet month weather wise so no nasty surprises hopefully.
As for groundschool, I've taken the decision to complete all my exams before I go. I really want to concentrate on the flying and as it is it's going to be a push. I started on air law but fell asleep

and am now on much more intersting stuff - principles of flight.
Thanks for all the honest feedback on here.
Matt