Unable to locate slide of Deltic hauled mk3s but found image of Class 86 hauled Euston - Manchester service back in 1974 at Stockport with mk3 prototype Buffet/Kitchen vehicle in a mk2d rake (4th coach) Also a shot of Western Class 52 at Exeter St David's on a Paddington service formed of mk2d air conditioned stock in 1975. Being new to this Iam not sure if I have been successful in attaching these, if not they are available to view in my pictures, also just to add these are poor quality screen shots as scanner has been playing up.
That's actually a very evocative shot of the 86 in the (presumably brief) overlap between headcodes being displayed, and the introduction of Mk3 stock - and very well spotted at that, the skirt being the main giveaway!
Remembering how often Westerns were still found on express work in 1975 - were uncomfortable, unlit, unheated and unventilated journeys out of Paddington quite commonplace with Mk2d air conditioned stock back then?