The details and routes of numbered services are set at around the year 1933. Some will have been extended and some curtailed before and after this date. So complete accuracy for any particular photograph cannot be guaranteed.

56

Peckham Rye
Embankment

Via:
East Dulwich
Denmark Hill
Camberwell Green
Elephant and Castle
Westminster Bridge
Return Via Blackfriars bridge (weekdays)
Westminster Bridge (Sundays)