Well I finally found case paper 61983. Exam 24298.
It was indeed from 1926 (out relief, address 39 Temple Street), and moved to a bundle in 1929.
As is often the case, it was rather disappointing. No new exam in 1928 or 1929 added.
Mainly is a list of addresses.
Percy Painter was a porter on the underground railway. I think it says he had been in the army 3½ years.