Hi Chas,
I worked on the CVR(W) Fox vehicles from when they came into service in the 1970's until they were withdrawn, as well as some privately owned ones since. At the Command Workshops we had the Royal Yeomanry ones coming through in large numbers and later on a number of other regular units with them. A delight to drive but not to work on. They were not good for spares, having to wait a long time, and I can see that there was never going to be the amount of parts stock as was with Ferrets and Saracens, etc. Engines and gearboxes were regular problems, and don't ask about changing the complete steering assembly!!
The Scorpion turret, from memory I think this is the story. Some Foxes were selected for conversion and sales for Mexico, as I recall, some of Royal Yeo vehicles. I believe a different turret was going to be used. I think the deal fell through as there were some turret-less Foxes sold at Ludgershall, with Scorpion turrets sat on top of them, the original Fox turret going on to the Scorpion to create Sabre, using an adaptor ring.
There is a book on the CVR(T) written by the former curator of the Tank Museum, Col. George Forty. It has a chapter on Fox in it.
The Scorpion Family by George Forty published by Ian Allan ISBN 0 7110 1175 3
regards, Richard