There's a case in point where did they all go ? apart form the odd 60cwt at Beltring you don't see them...........
In fact I've just remembered the last time I saw a truck that had a rear body like that it was 2004 at what used to be a very good Vintage vehicle show near Swindon where the OCMP used to attend in force. The truck turned up late in ex sales condition, the OCMP hung around looking for the owner but we never did make contact with him.............never did see it again.
Pete