Try to get posted to somewhere which has a RAFFCA flying club, then train for a PPL with IMC and Night Qualifications. Build your hours until you've qualified to start a modular CPL course with distance learning ATPL exam theory.
All of which you can do whilst in the Service.
Just before you leave, take your ME IR and MCC, then you will have a 'frozen ATPL'.
But before doing any of the above, make sure that you can hold a JAA Class 1 medical certificate!