Cider drinker has really opened up a few avenues of research. Here is a summary to date.
The subject title by some fluke appears to be quite accurate for one HYMAS family that migrated into London probably 1710-1714, possibly a little early from Leyton Essex. This was genuinely a surprise, it is confirmed from the two marriages of Samuel to Catherine HEWSON 4th Dec 1722 and it looks like his brother Edward to Catherine BIGMORE 8th Aug 1721 both in St Benett, Paul Wharf in part of Queenhithe in The City of London.
All 4 were from Essex as detailed on the marriage entries and both brothers Bapts can be found in Leyton, along with another 5 siblings, all of Edward and Rose HYMAS , who in several records is identified as taylor ( tailor) these Bapts from 1689 to 1702, in theory making the earliest migration 1702.
London Roll website currently has at at least 6 records relating to apprenticeships involving this family, even Edward to his father Robert.
Samuel b 1696 son of Edward is believed to be the Samuel who died circa 1772 with the will that summarises a family of possibly 8 children 1722-1750, and these associated marriages and Bapts of their children as detailed in the will are gradually coming to light . Still a long way to go to follow all the family through to the 1800’s. The Bapts of the children not yet identified in that period 1722 - 1750, hopefully they have serviced, but not on a current database.
I think it’s unlikely that this family is the only HYMAS/HIMAS/HINDMARSH or any approx spelling family in Lobdon in this period, but I suspect they form the majority of the people with that name.