Only a very few will get anything like 45K on the outside. I have several firends working in industry who are ex RAF and they are sounding notes of caution to anyone thinking of leaving.
Unless you have very specialised skills and/or some form of commercial pedigree your talents are not nearly as gold plated as you think. Also, if you go into industry, especially the Defence Industry, you more or less have to self fund your salary by bringing business in.
The hours and bullsh!t can be far more than in the service and your contract can be short term and very much performance based.
With more cuts coming, and far bigger then anything we have seen before, I would think very carefully before jumping ship.
As has been said, the grass is certainly not always greener on the outside.