Thanks for this trish1120.
The proximity to Somersham and the Thomas Assell as witness do look like this could be the Elizabeth Nevil b. 1743. I have been tracing the Assells/Assels as well. There are at least 5 children born in Somersham to Thomas Assel and Ann (no surname) between 1718 and 1726, including a Thomas in 1722. I haven't been able to find a marriage for Thomas Assel and Ann, presumably before 1718, so have no surname for Ann. However, I have also found 2 Thomas Assells buried in Huntingdon in this period:
Thomas Assell buried 20 May 1733, Huntingdon,
Thomas Assell buried 2 May 1734, Huntingdon.
I was assuming this might account for Thomas Assell snr (married to Ann) and their son Thomas, b. 1722, but your witness Thomas Assell shows other possibilities. I will have to try and find the wills of the 2 Thomas buried 1733 and 1744 to see if that makes thing clearer.
Thanks again for this added information.