Hi Graham,
I'm hoping someone in London, near the archives can help out there. I have looked on the site, but nothing jumps out at me for him in particular. Last resort will be to actually contact someone at the archives and employ them to do the hunting.
42/43 Brewer Street was long ago changed and after looking at an old map, it seems a restaurant is in the location now. As to whether it's the same building or not, no idea, which again, is why I'd love to get someone local to investigate the building, rates or any other business documents. It's definitely where he worked and lived as the insurance records mentions plate, linen, china, etc and the business storage etc at the back of the building.
As to the capital, we are still not sure on his parentage yet and would love to 'trip' on something that said "Money paid by......." but i'm not sure how likely that is, so on the one hand we are still investigating this family and it's origins and connection back to Edinburgh, the business information is the only bit I can't do much with being in Australia, apart from hire someone at the archives to look, and that will be done if no one else can help.
No Wills of any of the family have been found. Possible Wills for 'possible' relatives, but so far no mention of our particular family.