There are several negatives, of which this is one, depicting "wrong line working" but they are undated. The presence in this shot of the "old" triple bracket means that it must be pre-March 1955 and the sequence of negative albums suggests a date around (or after) 1953. If anyone has any additional information I would be grateful to receive it.
In any event 6022 King Edward III is in the process of backing its entire train over the crossover onto the up main. The clamp on the point is clearly visible close to the attending railwayman. Incidentally, this picture was taken on the Ross Ensign Selfix from the signal box steps. My father's Adams Reflex on its army surveyor's tripod is just visible on the right hand side.