The Chelsea death could be the son and there was also a possible Fulham marriage that I saw on the BMD for the son as a Charles A Thomas at Fulham.
There are no other births registered after 1912 Thomas, mothers maiden name Sands in Fulham. I havent found a death registered for Matilda Sands/Thomas either that fits.
1911 census Charles Louis Thomas/Matilda Thomas wife (!) is given as 10 Mund Street, Kensington. These were terraced houses in Booths time, desc. purple in his note book/maps - mixed wking. class poor but above the poverty line. Mund Street stands close to Earls Court exhibition centre. It is now the big Gibbs Green local Authority housing estate, Brompton/ Kensington. The streets were all pulled down as slum clearance in the late 1950's.
Katherine Thomas the divorcee and her girls lived in 47 St Georges Road, Kemp Town. In 1911 she was living on her own means and her daughters were not described as working. The house is a smart solid terraced house still occupied in this street of mixed residential and commercial properties.
Her daughters married at Horsham.
I wonder whether rootschatters know that they can look at properties on Google Earth and on Booths property maps of London (not outer boroughs) to discover the social history of our ancestors and the environments they lived in? Friths photo cards - nationwide, also show some streets in the Brighton area - many of which have now gone.
I reckon Matilda may have started as an employee of Mr Thomas when she returned to Heathfield from Tunbridge Wells around 1906 after the demise of her employer Rebecca Read..she started a relationship with him, got pregnant and he then left his wife

. Since Charles Louis Thomas knew the Brompton/Kensington area (where his wife had come from) that is now Earls Court he took Matilda back to that area - odd that he described himself as a farm manager - not many opportunities for farming around there!(although Earls Court - was Earls Court Farm in the 1850's) Its a fair supposition which further research may back up.
Funnily, I walked from the Brompton Road and down to Earls Court just 2 weeks ago!
Family history is amazing!

M.Ann