Hi,
I think that it's possible that William's name got misspelt somewhere in his lifetime. I have found this baptism, but there is no image there to check.
http://www.rootschat.com/links/01kjg/A Henry SAYERS married an Elizabeth WICKENS 10 miles from Slaugham in Horsted Keynes in 1805,
http://www.rootschat.com/links/01kjh/A Henry and Elizabeth SAYERS have a lot of children in Slaugham between 1806 and 1830,
http://www.rootschat.com/links/01kji/Charlotte 08 November 1807
Henry 04 August 1811
Ann 26 June 1814
Sarah 14 April 1816
Jane 22 November 1818
Susan 25 November 1821
John 21 March 1824
William 30 March 1830
There is this death,
Henry SAYERS Sep Q 1838 Cuckfield 07 192
Age: 66
Burial
Henry SAYERS
03 Sep 1838
Cuckfield
Age: 67
There is this family in 1841, Susan is transcribed as being 15 but I think the 5 looks different to the others on the page and it could be 18.
1841 HO107/1111/6 f.8 p.8 Cuckfield
Staple field Common
SAYERS
Elizabeth 50 Labourers Widow
Susan 15/18?
William 11
All born in County.
Then if this is the right family William loses his mother and sister while he is still very young.
Death
Susan SAYERS Sep Q 1841 Cuckfield 07 201
Burial
Susan SAYERS
18 Jul 1841
Cuckfield
Age: 19
Death
Elizabeth SAYERS Dec Q 1843 Cuckfield 07 235
Age: 57
Burial
Elizabeth SAYERS
28 Dec 1843
Cuckfield
Age: 57
Oh no...I've just found this death which could be the above William,
William SAYERS Jun Q 1845 Cuckfield 07 218
Age: 14
I still think the baptism could be correct as the date seems too much of a coincidence to be wrong.
I can't see any images or further info. on the above suggestions, maybe someone else with more local knowledge will be able to help.
Regards,
Daisy