Just so happens I looked in today and think I am familiar with this maker.
As seen from the carriages and centres on the attached photograph, it bears the hallmarks of Wastell Bros.of 235 Kingsland Road, Hackney.
This model looks more or less identical to Tann’s List 2a.quality and it may not just be coincidence that their factories were within a mile or so of each other.
The construction was the first 4-bend body style and was also used by Hobbs & Co. A single wrought iron plate bent on the horizontal plane and capped top and bottom by angle iron frames. The Tann version was also known as the MM Quality (machine made).
Tann employed 6 members of the Wastell family from 1907 through to 1943, probably after their business had ceased trading.
