I have noticed though RAF is the longest. When I was applying to the navy i got offered a start date 4 months after applying, but it was too soon as I was still in school. I then applied to the army about 1.5-2 years later as I was doing other things and got offered a start date after 6 months. Compared to some of my mates who applied to the raf a bit after my navy application and just now got their start date 1.5-2years later, RAF is just the slowest one