If it's a similar deal to the one I was offered a few years ago, the first thing they will do is "abate" your service pension. Which in my case, would have meant a significant pay cut.
Or, the "offer" of reserve service (High Readiness Reserve), where the RAF expected me to commute from the Far East at my own expense every month (£1200 round trip) but would kindly pay me a motor mileage allowance from Heathrow to Odiham..... for a daily rate of pay of about £45 a day, I think it was. Didn't take long making a decision on that one. In any case, there was no way they could have persuaded my employer to allow me time off to do it.
Anyway, I'm also age barred now, thank goodness and I'd far rather tinker about in the garage on my days off.