I've been out of the program for a while but back then the RN squadron would reform in 2018 and hit IOC by 2020. My point with the cadre in the US is that most (all?) will be considerably beyond the RoS and their careers, inside or out, are against the usual clock.
With respect to the training location it was accepted back then that the UK would only have the capacity to sustain the steady-state requirement. Before this point the UK would be reliant on US training to do the bulk of the heavy lifting. I would be surprised if that has changed as it would bog-down the UK F-35 force in conversion training for far too long. Clearly I am aware that the bean-counters saw UK training as the cheaper option but back then the impact on IOC, FOC and manpower sustainment was seen as too debilitating.