Go back to Helena Brown

This is the type of bike (with sidecar added) which Helena and Harry Royle owned c.1919 i.e. the post WWI period.
Their bike though is believed to have had a belt drive, not an enclosed chain as in this photograph.
War surplus Matchless motorcyle of 1919

Matchless 800cc / vee-twin, c.1919
Source of photo unknown. Assistance in contacting the owner would be appreciated.