David,
Have you thought of applying through the military route ie Worthy Down (or is it Shrivenham these days)? They might be the best people to ask as you would be paid the same as you are now* and get much better study support. If that's not an option, I'm told that the RG people are very helpful and they can give you good advice.
I won't answer your other questions as I would only be guessing.
Al.
*speaking as an ex-MOD civvy, that's far too much! :-) Yes, I'm jealous.
