I hate to tell you this old chap, but as a Flt.Lt. Eng.O you're probably not all that employable in the civil world.
Maintenance managers jobs (essentially a SEngO or JEngO equivalent) in the civil world only go to people with CAA licenses, in addition to management experience.
Technical engineering jobs go to people with several years detailed technical experience (designing or testing things) as well as their Aero-Eng degree.
So unless you're (a) an ex-airman who got civil licenses on the side, or (b) have spent your last tour (or more) in a very technical engineering job somewhere like Farnborough or Boscombe, you're only likely to get either an entry level graduates job, or a non engineering middle management position. Either way, you'll find the money is at best 2/3 of what you get at present.
G