With a class 20 in the background which looks very ex-works and appears to be 8174. I cannot recall these being at all common in the area in the 1960s.I don't think this can have been taken 1965 as originally thought. The peak has lost its D-prefix, the class 20 wasn't delivered until Nov 1966 and it also is green with full yellow ends (as is the class 40) which it would not have acquired until after 1968.Maybe 1969 or 1970?