William must have died after Betty was born, so after 1784. There are only two Saddleworth Burials for William (after 1784 and an adult). However there are many William Buckley deaths (9 on GRO index 1837-1840), so burial records must be missing.
Name William Buckley
Event Type Burial
Burial Date 4 Jan 1801
Burial Place Saddleworth, St Chad, Yorkshire, England
Reference Number O9/1/4/1
Item Number 6
Archive Roll 909
Abode: Shaw Hall Barn
and
Name William Buckley
Event Type Burial
Burial Date 5 Sep 1803
Burial Place Saddleworth, St Chad, Yorkshire, England
Reference Number O9/1/4/1
Item Number 6
Archive Roll 909
Abode: Greenacres Moor