Andy, if you are already a qualified electrical engineer, than I would suggest joining as a Gen Tech E, as that is your closest ground trade.
Aircraft Electrical engineering is a job for one trick ponies, and will not give you the variation that a ground trade will give you.
Do you want to give anything else a go?
Also reference the RAF Regiment comment, leave it well alone, as its crap.
The pensions are just about the be changed, as they're costing the MOD a fortune, but like the Government, they need to make cuts somewhere and guess who's going to get bummed!