Hi everyone,
Sorry for the extremely long gap between posts. Since last posting here, I have been lucky enough to have been contacted by Jacquie Bly who added the original source on IGI/Familysearch referring to the tree compiled by George William Todd.
Jacquie explained that George William constructed the tree from a box of papers he found in the attic and that she copied large parts of it from him. He died without children in 1996, and Jacquie does not know what happened to the original tree or the sources. Even so, she very kindly sent me hard copies of what she has.
As noted in my original post, this gives the parents of Thomas Todd as George Todd and Mary Strover. It also has George's parents as Henry Todd and Frances Williams.
A large part of the tree shows the descent of Frances Williams from John of Gaunt. The crucial part of this is the last two generations. Frances' father is given as John Williams, grocer in London d 1733 and his father as Roger Williams, merchant tailor of London d 1705. Unfortunately, I can't find any trace of either of them (or of Frances). Roger's father is well documented, Sir Griffith Williams bart d 1663. You can see him in Wikipedia here
https://en.wikipedia.org/wiki/Sir_Griffith_Williams,_1st_Baronet and in Cockaines' ‘The complete baronetage’ here
https://archive.org/stream/cu31924092524390#page/n25/mode/2up and here
https://archive.org/stream/cu31924092524390#page/n231/mode/2up.
The circumstantial evidence in favour of this is the frequent occurrence of the name Griffith in the family.
The tree does not have parents for Henry Todd and the parents it has for Mary Strover are different from those that I originally mentioned, and which everyone helped investigate. George William had them as John Strover of Rochester and Anna Searles, who inherited the manor of West Court, Gillingham. George William gives three generations of Anna's ancestry, which can also be found here here
http://www.british-history.ac.uk/survey-kent/vol4/pp226-249.
I think that George and Anna married at Gillingham on 13 July 1748, which to my mind makes them a little old to have been the parents of Mary Strover whom he, like us, has born in Rochester in 1770. I am inclined to think that we had the right parents before, although it is very likely that the various families were related; I have Mary's parents as John Strover and Ellin Cresswell, her step mother as Elizabeth Searle and her paternal grandparents as Thomas Strover and Mary Sales.
George William also gives George Todd the stockbroker two full brothers, John who is said to have emigrated to the US and of whom no more is known, and Griffith Henry. I differ with the tree on the details of Griffith Henry's family and also on his parentage. His is the only record I can find for this generation: he was christened at St Martins in the Fields on 28 Feb 1773, parents Henry Todd and Mary, not Frances.
Jacquie usefully pointed out that George Todd's son Willliam was also a stockbroker (will proved 18 May 1833) and provided lots of invaluable detail on the later generations of the family.
Meanwhile, I have ordered a scan of the Bills in Chancery for Strover vs Todd and spent ages tracking down the original images of the 'baptisms' on 28th April 1835 that Lilly found, only to discover that I had them attached to my tree all along; they were not baptisms, but rather birth registrations at Dr Williams' library. Even so, the fact that the births were registered on the same day supports the link between the two sets of parents. I have also tried and failed to find a birth or christening for Ellin Cresswell or anything other than a possible christening in Rochester for her brother William Cresswell appointed executor of Thomas Strover's will.
Naturally, I will let you know when I get the Strover vs Todd stuff from the National Archives. If anyone can help with any of the rest, I would be delighted.
Thanks in advance,
Alan