Eastern National 2608, KNO949C, Bristol FLF / ECW CH37/22F seen here being prepared for conversion to bus 2940, which wasn't completed until a year after this photo was taken. New in March 1965, withdrawn September 1980.
Also in the photo is 2791, AVX959B, in overall advert for the National Coal Board, ready for repaint into fleet livery.

Photo taken by Eric Thompson, July 1975