I'm not an expert on UK genealogy, but there are a few things I might suggest.
For Latvia I would look at my Latvia resources:
There is of course the JewishGen Latvia database, and multiple Facebook groups dedicated to Latvian (and Lithuanian) genealogy.
My own Silver grandfather came from a town in Poland that was part of the Russian Empire before WWI. In Poland/Russia his surname was Zylberman. That was changed to Silberman, and finally Silver.
I was only able to find my family ancestral town because it was in US naturalization papers. Are there similar papers for the UK? Its possible both spouses have information on their origins in such papers.