The 24 or so months is the period during which you will complete the various stages of your application and wait a little while for your place at HMS Raleigh. Once your training has begun, you then need to add 10 weeks plus 26 weeks for your training and then you're good to go. In total then, roughly 3 years.
Just an aside!! never knew they had Chefs in the navy??? Just cooks, right up to Chief..... Although we did sometimes call them chef, when they were serving, and you were trying to finesse an extra portion out of them :laughing2: