I have had another look for the possible baptisms but it is still inconclusive, there are trees on Ancestry but even these vary, most of below I have already posted but there are a few extra bits of information. It is always possible that the records have not survived.
The marriage record on Ancestry is one of the worst transcriptions I have seen, it reads that William Henry married Susannah, even though his name is fairly clear but more importantly he signed very clearly William Stacey, Susannah made her mark.
William Stacey & Susannah – baptisms St Peter Chertsey, Surrey
George 3 Apr 1768 burial 1 Jul 1768
Hannah 18 Jun 1769
William 25 Sep 1771
Mary 20 Mar 1774
Sarah 14 Nov 1784
This is the only burial I can see in the County?
William STACEY Burial, age 83 (1746) 18 Mar 1829 Surrey Camberwell : St Giles : Parish Register
This earlier?
William STACEY Burial 02 Apr 1809 Surrey Chertsey : St Peter, abode Botleys
Susan STACEY Burial age 74 (1743) 14 Oct 1817 Surrey Chertsey : St Peter
NB- A William Stacy & Sarah Fray had children baptised there in the same period.
When they married at Kingston Upon Thames in 1766 they were both otp & widowed
A William Stasy, son of Thomas & Elizabeth was baptised KuponT in 1733.
William Stacey likely married Sarah Stacey first in 1755, Sarah died in 1763.
Sarah STACEYWilliam STACEY Marriage 18 Aug 1755 Surrey Kingston Upon Thames
Sarah STACEY Burial age 73 (1741) 13 Oct 1814 Surrey Chertsey : St Peter
The only other earlier Stacy records on freereg at Chertsey are two burials, Robert in 1719 and his wife in 1710.
Colin