Hi, I have read through this interesting thread - did you know there is a Manchester/Salford directory for 1929 on Ancestry?
It only has three entries for Clifton St in Salford (45,47 and 2) but there is also a Clifton St in Stretford which would probably be the nearest Clifton St to St George's Church in Hulme.
There is a William Smith listed at 95 Clifton St in 1929 - could he be the same one that married Edith Higginson in 1911? As has been said, hard to be sure with a name like Smith!
I'm not sure where electoral rolls for Stretford in the 1920s would be, if not in Manchester - Trafford local studies maybe?

Barbara