Jacko,
'...or was not until the number of units to be re-equipped went from 7 to 6 frontline squadrons.'
When did the number of intended frontline squadrons reduce? I've not seen any source quoting this (NB - I'm not doubting what you say!), so a steer would be of interest. Most of the sources available at the moment that I can find still suggest that Coningsby and Leeming will have two front line units apiece, with three at Leuchars.