Bob
The advice to look at the Personnel Manual is good. Used to be called Mod Manual 2. These are entitlements, so don't be put off by the little Adolfs whose job it is to pay you as little as they can persuade you to accept. As a C2 (Sqn Ldr/Lt Cdr/Major equivalent) you are entitled to first class travel - don't set a precedent for yourself by accepting less. The relocation package is poor but check carefully what used to be called "Excess Rent Allowance" which pays you a monthly sum for 5 years, reducing to zero after 9 years, to allow for the difference between house prices. If you are moving from a cheaper area, you may qualify. Get everything in writing.
Finally, be aware you can negotiate salary starting point. Don't just accept starting at the bottom as you will find you earn less than your staff. The pay scales are overlapping so go for the top end. The criteria is experience and whether the job is difficult to fill. I'd say these are as they are always having to advertise in the press.
Good to see MoD have recognised the skills needed to do this job. The posts used to be one grade lower. Best of luck.