I don't know if this has been mentioned before but the Railway Roundabout film's include a sequence shot at Seaton Junction where a three coach portion for Seaton includes a Maunsell Restaurant Car in it.
On rechecking it's one of those lettered as a buffet car.
It's a Hornby paradise- rebuilt and unrebuilt Battle of Britain's,S15s,and M7s plus aWarship on a full rake of Hawksworths!