"If anyone can justify it with reference to figures please come forward".
Of course nobody can. How can anyone justify spending £££££ to just be in a position where you might be lucky to get an interview for the job you really want to do, (which probably pays considerably less than the job you are thinking of leaving)?
It's a risk - try a search on this forum for the phrase "there are no guarantees"
It's not about the money/justification. If it is, then I suggest that maybe your decision is actually a quite easy one.
If it was guaranteed for anyone to be able to walk into the RHS having spent a certain amount of £ on their training, I'd seriously reconsider getting on an aircraft again!