I dont know what to think!
Carol and I have retraced the path you have taken, and if that marriage says Henry is a Painter then it certainly looks like the right one.
But something doesnt seem right to me. They were living as a couple in Etham Street, well at least little Louisa was born there, and they pretended they were married when registering her.
They are still at that address on the census.
Why then, when they married, between these two events, did they go to Bethnal Green? OK, not that far.
It is not, as far as we know, to be married from her parents place -they were in St Lukes. And it does not look like family were witnesses. And she has lied about her age, so unlikely her parents were involved at all - if she had their blessing she would have given her correct age and had their consent. Witness, as Carol suggested, may even just have been someone who was around on the day for a different wedding.
But - they must have lived there for three weeks at least for the banns to have been read.
Seems odd, they were working class, so would probably be renting rooms at Eltham Street, they would not have afforded to pay for more accomodation in Bethnal Green.
Why didnt they marry locally?
Speaks of running away to somewhere they were not known to marry.
But with the arrival of the baby just a month or two before, you would have thuoght family etc would be keen for them to marry a.s.a.p.
I have struggled to find the possible James and Susannah in later censuses, just to see if anything comes up to help. found a 25 yr old Susanna Anderson, bn St Lukes, in Spitalfields RG10 503 14 22, might be her sister though age out.
There are loads of Andersons bn St Lukes around.
Looks like either Sarah died and James remarried to a Susannah, or the names got interchanged. Or maybe the census is wrong - we dont have others to compare!
I can see your frustration on this - it is so close but somehow has that element of doubt.
Will keep thinking and looking, and I know Carol will too.
I am just about sure yuo have got the right family - but would be so much better to find some other evidence.