I'm beginning to realise how incomplete my family-records are: all I have in reply to your query is that William Frankis, b.1798 at Upton St Leonard, had a son Charles, b.1821, who in 1845 m. Hannah Breen; there may well have been other children of William of whom I have no record. William was a farmer at Upton SL, Charles became a ropemaker and set up business in Highworth, from where his eldest son George (b.1847, my paternal grandfather, d.1925) moved to Norwood, London. The William you mention as having married in 1801 must presumably belong to the previous generation. 'My' William, b.1798, was the son of Thomas, b.1778 in Gloucester, and Thomas had an elder brother William, b.1775, who may well be the one you mention as marrying in 1801 (I have no details of his marriage and subsequent life).
I have no record of Edward, b.1810: he couldn't have been a son of William b.1798 (or as you ask, a brother of Charles); William's youngest sibling was a sister Emmalia, b.1810; I assume that your Edward (ancestral to your wife?) must be a cousin of William.
Clearly the Frankis family was very prolific in Gloucestershire and Wiltshire, and it's likely that more than one branch had sons who settled in London in the second half of the nineteenth century. That is presumably the explanation for the Frankis family in Bethnal Green (see the posting before yours).
My first posting in this forum was in response to Bridget Paling, who clearly has more information than I have (Bridget, where are you?).
I’d be pleased to give you what information I have so as to conflate it with your own records.