Does the term daughter in law possibly mean step daughter because I am sure the Ann described was not married & married William Edward Jury in 1812 & one of the witnesses was Elizabeth Cramp.
I haven't looked at the whole of what you have posted but did look into this Ann.
Daughter in law certainly can mean stepdaughter in this period. It suggests that John Cramp's wife at the time of his making the will was previously married to a Cramp and had Ann before her marriage to John.
That points you straight towards the marriage at St Mary Whitechapel in 1800. I would make this your research priority.
Do some work on the witnesses in 1800 -
Thomas Cramp and
Ann Organ. Look for their marriages and see who else was there. Also check through Cramp and Organ wills.
The 1800 marriage was by licence, so there would have been a corresponding Marriage Allegation and Bond. The Allegation in particular might give you an occupation for the groom.
Unfortunately I can't find these records in the
London and Surrey, England, Marriage Bonds and Allegations, 1597-1921 collection on Ancestry. They may be in other collections of Marriage Bonds.
Otherwise, if you can find a marriage for the daughter Elizabeth, you can compare her signature against the witness to the Jury - Cramp marriage.
I did glance at a tree for William Jury, just because it came up on the search for his marriage. This tree simply took his wife to be the daughter of the John Cramp of the 1809 will - ignoring the wording of the will.