Estimated date, Tony Wardle is pretty sure this is approaching Norwich from the Ely direction and the train was likely to be either the summer sat train from Newcastle to Yarmouth or the one from Manchester. Peter Hall doubts if it would be the Manchester train as this was diagrammed as two class 25's to Lincoln with loco off March taking the train forward until 1979. Two BGs also suggest the Newcastle-Norwich/Great Yarmouth service.