You don't seem to have had much luck here mucker.
I've done a few Tamiya 1/35 scale Chieftains in my time apart from the seventies NBC pack they've all required extensive turret rear rebuild. To get a photo of a particular reg No may be a tad difficult. I suggest that if the mark is known go for that, if your pal is a good model maker he should be able to go with that simply changing the reg No and any callsign info. If you need decent photos of a particular part of a chieftain give me a shout mate.
There is a very good book about 'Chietian' called 'Chieftian' by Rob Griffin ISBN 1-86126-438-0. It covers all the development & history & according to the list your old tank is at Castlemartin hopefully not as a hard target. Good look