Hi
Are you sure about the dates - If born in 1731, she would have been almost 50 when she married and had the child.
There is an IGI marriage - extracted record for Thomas Wildblood & Sarah
Geater 15 Feb 1779 and a child Thomas baptised 5 Dec 1779, both at Stoke on Trent. There is another Thomas, christened 10 Oct 1784, also son of Thomas and Sarah.
http://www.familysearch.org/Eng/Search/frameset_search.asp?PAGE=igi/search_IGI.asp&clear_form=trueThere are a number of submitted IGI records for Sarah - all giving birth dates from 1740-1750, but it seems doubtful a parish record has been sighted. There is also an extracted record for a baptism for Sarah Gater in 1735 - parents Thomas and Mary. This seems a slightly better option but she would still be 45 when having the first child.
A family search gives 6 children to Thomas and Sarah, the last being baptised in 1789, so I think the 1730s birth is rather impossible - unless I am mistaken and there are 2 Thomas & Sarahs

You did mention Thomas Snr - is there also a Thomas Jnr who married a Sarah?
To do a family search, put thomas Wildblood in the father column, Sarah in the mother - give a date e.g. 1780 +/- 20 and a location, BI England Staffordshire - this will give all the children in this time period. (apologies if you have done all of this)
Trish