Tony,
Thanks for posting picture of the photo, it certainly looks like 01 CA 78 and I have checked my service records which although strangely seem to begin in 1964 and is complete from that date, this Ferret was actually in service from Feb 1959. It begins with Nov 1964 Guards Ind Para company then May 1966 Para Sqn RAC, who I now understand were in Aden at that time and got their Ferrets from Ind Guards coy. So thanks to your picture you have managed to fill in a bit of history for this Ferret.
01 CA 78 is alive and well, and I have had the pleasure of looking after it for the last 3 years after she was restored by a guy called Andrew Deacon back in 98/99 when she was in a terrible state. Andrew did a great job restoring her and apart from the odd leaks of oil it runs great, is very complete and is in very good condition.
Is it at all possible I could get a copy of your picture and your permission to enlarge it.
best regards Terry