Went recently (this last summer). RAFCARS/Managed Path didn't appear to do anything from the RAF side, on the BA front it let me go to interview with up to 2 years to go, even if I hadn't had a medical and ATPL. No 'benefit' after getting a shot at interview of course, but you tell them when you're available to start and they'll give you a formal job offer with a couple of months to go that date if you've been successful/lucky.
Virgin seem to be hiring mainly type-rated guys at the moment with a few others being kept swimming in the hold pool.
BA are hiring only for short haul (or the 757/767 fleet if you're lucky), long haul seems to have dried up for new arrivals as the 777 gets more popular with people on internal postings bids. That may change again though as it looks as though they may have finally sorted out their pension deficit problem which allows them to buy more aircraft if they want too - and apparently they want to! Good news for people applying to start in 6-12 months time.
I haven't heard of RAFCARS helping with any of the other airlines, it's the applications you send out that do the most work
I kept annual leave, applied successfully to carry over some of the unused stuff from the previous year, used resettlement time and terminal leave and was left with a pretty big window to work out a start date overlap/world travelling experience (about 4 and a half months).
Hope that's of some use. Good luck!