Au contraire, the Mk 3 S had its own body number prefix so that would be a great help. The chassis number prefix is that of a Mk 3 Cooper S as is the 12H engine number quoted - I don't know what you former colonials got up to with chassis number prefixes but only the Mk 3 S used XAD1 in the UK. Lesser models had different prefixes.The body number prefix won't help much. The round nose cars all used XAD1 by that stage, while Clubman cars used XAD2. The engine number in this denotes a 1098cc motor. Also, looking at the car, the reflectors and front turn signals all point to being a South African car.
Similarly, XAD2 was only used on the 1275 GT in the UK, and not on the Clubman saloon or Estate.
Edited by 62S, 18 December 2015 - 11:42 PM.