Another nice pic showing three people enjoying themselves with their Norton and sidecar outfit. The registration appears to be WK9272 or WX9272 which dates the bike at 1929-1930. The sidecar looks more modern than that though.
As the exhaust pipe sits very high it must be an OHV model; the 8" Enfield front brake and the George Dance knee grips (that can not be easily fitted to the tanks of other models) identify the bike as an ES2 or CS1 (thanks Simon)
