Hi Ryan
There were two 'Petty Frances' in London, one in the west around Westminster, largely a community of soldiers, clock makers, goldsmiths, silversmiths, and one in the east largely made up of Silk Weavers and Manufacturers. There were smaller communites elsewhere, such as Chelsea, Hoxton, and across the water in Wandsworth there was a small community of Huguenot Felt Makers and Millliners. It's true that some families did have links to both Westminster and Spitalfields.
I have heard it mooted before that the Spencers Silk Weaving in the East End were of Huguenot stock, and it was originally Despencer. I've not actually found any evidence of that though. The particular family I researched seemed to be native English from Essex. Also this is a very broad, (but not entirely innacurate) generalisation, but I have found that the French families tended to live clustered in Spitalfields and Bethnal Green, whereas the English weavers, who were equally numerous were alot more predominate in Shoreditch. This was perhaps a division more pronounced early in the 18th century, and which slowly dissapeared altogether in the second half and early 19th century as the two communities intermarried more and more and eventually blended into one. I think if there is any truth in the Despencer tale it is probably the fact that the English Spencers may originate from the Norman Despencer family who certainly did come over many years before, and were infamously linked with Edward II and his endless succesion of troubles.
Do you have any particular reason to think Thomas Spencer was a Huguenot decendant, apart from the area and the link to weaving? He may well have been, though perhaps through his maternal line?
Regards
Richard