The RAF has been posting first tour instructors directly back into the training units for most of its existence. As far as I am aware all such individuals completed basic and advanced training before being posted to CFS for QFI training. This applied to both the fast jet and multi training streams.
In 1964 I was posted to CFS on completing multi AFTS at Oakington as a so called creamed off (scummed off to the majority) NCO pilot. This involved a quick return to IOT at South Cerney for a (5 day) commissioning before CFS, as the system was averse to first tour NCO pilots teaching officer students.
By coincidence, after graduating as a brand new scummed off JP B2 QFI, I was posted back to Syerston on the same Flight from which I had been trained only 14 months previously. Many of my earlier instructors were still in residence!