Difficult to say which Company owned this bus, but if it was the Loftus Company, then they eventually went bust and their assets were obtained by Mr Keith Watson at Saltburn. When his Bus enterprise failed they were all bought up by what went on to become The Saltburn Motor Services being taken over in August 1974 by Cleveland Transit. This company in turn becoming part of the Stagecoach group which no longer serves East Cleveland. How the wheels turn.
Image courtesy of Stan Ward (via Carlin How Community Centre), thanks to Chris Hall for his update.
The ‘PT’ prefix series of registration numbers was issued in County Durham between November 1922 and July 1927. As the bus looks new, I would suspect the photo was taken during that period.