Do you really have this many rellies Philezra?! I wish I was so lucky.
About this couple, do you know anything else? if they are ancestors, a child? or is Thomas Hender a sibling of an ancestor ... ?
The 1861 household headed by Robert Wynhall in St Martin is
Robert Wynhall born abt 1821 East Looe a sailor and ?
Mary Wynhall born abt 1826 East Looe (East Looe is a ditto for all other household members)
Philip Hender son-in-law 16 East Looe (i.e. stepson)
Ellen Hender daughter-in-law 13 East Looe
William Hender son-in-law 11 East Looe
(the other two women shown by Anc'y have nothing to do with the household)
This is the Hender household in 1851 in East Looe -- the surname was corrected from Wender to Hender by an Ancestry user in 2010:
Thomas Hender abt 1824 born Callington a matchmaker
Mary Hender abt 1826 born East Looe
Philip Hender aged 6 born East Looe
William Hender aged 6 Mo born East Looe
(where's Ellen?)
The info for Mary matches the baptism of Mariana Trout daughter of Philip and Susanna in St Martin by Looe 1825, at the OPC site.
Mary is still with Robert Wynhall in 1871, and her father Philip Trout is also in the household.
There are also two Wynhall children born after the 1861 census. (Another Ancestry user has corrected the name from Wynhhall - it seems there are people who have info about this family.)
Since there seems to be no marriage for Robert Wynhall and Mary, one suspects a simple estrangement between Mary and Thomas Hender, and therefore no indication of whether or when Thomas Hender had died. The site Claire linked to says the couple married "c1860" which is just laziness; no marriage appears to exist.
Robert Wynhall was living with his parents in East Looe in 1851 ... but he is married with no wife present. Likely the marriage was 1848 in Liskeard reg dist. He married Elizabeth Edgecombe; she is visiting with her parents in 1851 in Morval, born c1828.
So Robert had a pre-existing marriage (i.e. was not widowed) that could have prevented their marriage, and this doesn't help us determine whether Thomas Hender was still living when Mary partnered with Robert.
Robert Wynhall died at 70 in 1890.
Mary Wynhall died at 76 in 1903 - both in Liskeard reg dist.
You could always contact the person who owns the site Claire linked to, directly ... although I could understand being a little leery.
http://www.hunterscastle.com/