This is where this kind of research comes to the fore. Unfortunately it's often only with the passing of time that recording of such information is seen as important by many of those best placed to do so at the time - a fact I try and impress on as many as I can these days to try and make researching that little bit easier in the future.
It could have been one of two aircraft that you flew in: XM295 and XM296 were both at 27 MU Shawbury in mid 1968; both of them were ex-Queen's Flight, with for former being sold and eventually re-engined (ugh!) and the latter being transferred to 60 Sqn at Wildenrath. They then relinquished XM296 to the RN who operated it until the type was withdrawn from use and she currently resides in the USA - still airworthy, I'm glad to say.