Unfortunately you will find that once you get outside you might not find the time to do the required amount of study for your Licence exams. I assume that you will get some kind of terminal leave, etc. Your best bet is to use this time to get onto a licence course so that you can hit the exams hard and fast. Your Military training will stand you in good stead for this, as an ex-RAF guy myself I know that you have been trained to a high standard, now you need to convince the CAA and the only way to do that is to pass their exams.
I would start at the beginning and work your way through them in numerical order. Maths, Physics, electrical fundamentals etc.....
If you are a mechanical trade then I personally found it best to get a pro to teach you the Electrical and Avionic type stuff in a classroom envoiroment, Air Legislation is also best taught by an Expert (imho) as it is an incredibly boring and difficult subject to self study.
I was an Airframe fitter in the Airforce and found that electrical stuff quite hard at first. I am now a full B1 ( after I converted my single BCAR Aeroplanes 2 Lic). I now find that nearly every snag i deal with on our Aircraft is Elecrical, Avionic or Engine related, You soon learn fast !
It is doable and plenty of folk have made the transition, the question you need to ask yourself is do you want to earn £20K pa or £40K for basically doing a very similar task, that peice of paper is worth an awful lot of money in the long term....
I imagine that 2005 seemed a long way off back in 2000 when you would have been able to use some of your training and experience for the BCAR exams, we live and learn , eh.
The fact that you're doing something about it now by asking the right questions in the right places is a good start....
Good luck , you're gonna need it...