From the Archdeaconry Of Lewes Marriage Licences 1679-1729 which is a typewritten record
July 9 1686 marriage
Henry Warwick of Chayly, carpenter, & Grace Coulstock of Hamsey : sureties, said H. W. and Edward Langridge of Hamsey, husbandman (Hamsey).
The very next day, Grace and Henry had a daughter baptized (10 Jul 1686) in Chailey.
Grace, wife of "Henery", died in June 1688.
In the will in question, I agree it is written Cowlstocke, but now you know to look for records with "Coulstock" as well!
Snip from the will: