This shot must date from around 1950 and shows 22 with the full-length upper-deck advert which was common on the pre-war fleet and also appeared on some utility vehicles. Flour seems to have been a popular product to advertise this way and this particular brand is still popular today.
22 later lost this advert but on the later offside view of the bus the outline of it can still be made out on the front panel.
Photograph courtesy of the Bristol Vintage Bus Group.