Several thank you's!
John - after initial problems I gained access to the microfilmed copy of the Withyam registers; wonderful to see the original document online. I probably need to do the same detailed search on the Rotherfield registers.
Artifis - thank you for taking the time to do the searches and for your valuable suggestion that one of the couple might have been a minor. I'll keep in mind the Sarah from Kent.
Little Nell - thanks for the Muddle family website which is truly wonderful.
Sarah Muddle, daughter of Thomas the clockmaker, who inherits ten pounds from his will, is I'm sure the 'second' Sarah who is baptised in 1718 and still single at the time of his death. She can't have married in 1729 and I can't see that there would have been a late baptism when all her siblings appear to have been baptised not long after birth.
The website
http://theweald.org doesn't attribute any parentage to the Sarah Muddle who marries William Hider.
However, the Family Search website has trees that attribute Sarah Hider (née Muddle) to the clockmaking family, as do several trees on Ancestry. On the latter this Sarah is sometimes referred to as 'Sarah Elizabeth' but no source documents are noted. I suppose it is possible there were two children named Sarah...
I'm left wondering if there are clues in the names of William and Sarah's children: their first three children are named Sarah and Edward and Mary.
Also wondering if a marriage by licence would have determined the church? A Joseph Hyder (sic) and Mary Ralph, both of Rotherfield, are married in Withyam by licence on 13 Jan 1730. Perhaps once again a minor involved in the marriage?
Cheers
Mumfy