The first FGR2 squadron was Shiny 6 and they took that identity early in 1969 from 6 Sqn Canberras during their OCU course to maintain the unbroken service record of 6 Squadron - looks like history is to repeat itself when 6 Jaguar Squadron moves to Coningsby, presumably to seamlessly become 6 Squadron with Typhoons.
I remember, I think, that 43 Squadron formed with FG1s just a little later at Leuchars, but it might have been earlier.
The non-stop Singapore trip was flown by 54 Squadron who then held the London-Singapore record for a few hours until British Airways (or was it BOAC then?) beat it the following day. They didn't need to go so far to stay within the dip clearance rules. Not sure how many refuellings they did but it was about 15 hours. I did the trip a much better way earlier than them, staging overnight in Kokinelli land, Dubai and Gan. Short range bladders most fighter pilots.