Hello
I've found the marriage on my CD which has Twyford.
Strangely, it give the witnesses, William Hyde and John Fox. It gives the date as 7 April 1799 however.
There is a christening in 1770 for a William in Twyford, not sure if this is your man, but parents were John and Eleanor.
There are quite a lot of Greasley events on the CD for Twyford. Here are some children born to William and Sarah (may not be your William/Sarah)
Eleanor 22 Jun 1800 (there is a death which may be her - 4 May 1811. It gives the abode as Thorpe Satchville. This death also gives parents as William/Sarah)
John 27 Jun 1802
Mary 4 May 1806
Sarah 8 Jul 1804
William Beeby 13 Jun 1808
Hope these help
Kind regards
Sam