I'm in a similar position to you Joe, but slightly further downstream. Just finished the 14 ATPL theory exams and start CPL/IR flying in January.
The first thing I would say is do nothing about professional licences until you have a PPL. You may find you do not like it as much as you think you will: I know of people on integrated courses who have never flown in a light aircraft and it's a expensive gamble (circa £65k plus living costs) if you get it wrong. If you've got time on Det, then I recommend getting hold of the AFE PPL manuals by Jeremy Pratt - very easy to digest and help you get ahead of the game. But I would not go deeper than that at this stage.
If you have not chosen a PPL provider then absolutely use a RAF Club (
http://www.procommercesolutions.co.uk/raffca/homepage/) - Akrotiri is dirt cheap I was paying £40 for a C172 out there! Plus you often get taught by RAF QFIs who I have found to have far more exacting standards than civvy clubs: this measn you learn excellent skills from the outset and hopefully save on resits later.
The next thing you should do is spend a few hundred £s getting a Class 1 Medical from the CAA: as serving aircrew you should sail through it, but best to make sure before you waste a considerable amount of money.
Then you have a tough decision to make. Either leave and do a fulltime course (integrated or modular) or do a modular course on top of your day-job. There are lots of threads on this - it comes down to personal choice, how you prefer to learn and your circumstances.
If you choose to go modular then can you qualify for ELC? If so, I would recommend arranging your training to ensure you maximise the 3 entitlements over 3 financial years. For instance, arrange ATPL theory one at the end of one FY, CPL towards the end of the next, and IR at the beginning of the 3rd. It's worked for me. You can also use SLC for exams etc (£60 a go for ATPL) and get just over £500 for resettlement as well.
Learning wise, leave it until you have your PPL then bone up on your maths and physics - nothing too difficult with the study, volume is the problem. Don't forget you will need to hour build if you go modular which will give you time to start studying from course books available via ebay (Oxford and Jeppesen regularly available and both very good). I found the EFTS maths and science books excellent for prep. The Met Sect at most of the flying units also do a good line in manuals.
Hope that helps, and best of luck.
RD