Thanks everyone for the suggestions.
The link to a post with my data card is here:
http://www.sl113.org/forums/index.php?topic=18587.0As you can see, there are two dates and someone kindly provided a likely explanation as to why there is a January 1968 and a September 1968 date on it. One is probably delivery to the dealer and the other is sale to the customer.
Given that, I'm assuming the date of first registration might be the September 1968 date. That (probably) has implications for subsequently registering a car in the UK because the UK system at that time had a suffix registration system that followed A,B,C,D,E,F,G etc that changed with the year. The change of letter occurred on 1 August every year.
If my car was actually registered before 1 August 1968, it would have had a registration plate ending with an F. After 1 August 1968, it would end with the letter G.
So, I'm just anticipating problems establishing the true 'age' of the car for the purpose of getting it registered in the UK as to whether the Agency should issue an F or a G plate.
It probably doesn't sound material, but I know they can be picky about plates that show a car that is 'younger' than it really is (i.e. it is not allowed).
If there was some way of establishing from the original German agency when exactly this car was first registered in Germany, it might help.
WRe, thanks for the kind offer of assistance, I might be drawing on your German expertise very shortly.
David