la calda
According to one of my books of words on the F4, the Phantom FGR2, first entered RAF squadron service with 6 Sqn, re-formed at Coningsby on 7 May 1969. Obviously there was an OCU formed prior to that (228).
The FG1 first entered RAF service when 43 Sqn re-formed at Leuchars on 1 Sep 69.
These are dates for entry into service, ie declared on the Battle Order, so there would have been much work-up performed before that which is probably when you saw them.
The FG1 OCU function was performed by 767 Naval Air Squadron at Yeovilton, who trained both RN and RAF crew for the FG1. This unit was formed on 14 Jan 1969 and disbanded in 1972. Any crew going to 43 after then had, in effect, two OCUs, one at Coningsby on the FGR2 and a conversion to the FG1 on the squadron at Leuchars.
Hope this helps
jf