Well done Billy Girl!
Not sure whether you can get career advancing loans or not... but do you know that as of September we now receive a monthly accomodation allowance on top of the 10K? It's not a huge amount but have found it enough to cover the rent down here, so that helps a bit.
The majority of trainees b&b it for a few weeks, and then many get together and house share. You will need to think carefully about renting though, as the minimum contracts tend to be for 6 months, and you could find yourself stuck if the course doesn't run to plan or if you end up holding somewhere else between courses/recourses.
As for course prep... you will probably receive a distance learning package from NATS in the near future (we were sent a navigation package) and you will need to know that inside out for the start of the course. In addition you could get a head start by looking at spotters guides as you will need to be able to recognise a variety of a/c and helicopters from photos (for the aircraft characteristics and performance exam). It's also a good idea to retain the information you were given to learn for the interview process as it will feature in your theory lessons - eg. radio nav aids (VOR, DME, ILS etc).
Hope that helps!