Comments

Thank you for the confirmation that Mary SINGER was William's 2nd wife, that makes sense. I will certainly be having a deeper look into this tree.  

Looking at the Marriage Records for Huntspill on our site I see that a Mary HEMBERRY[sic] of that parish was married in 1792 so that probably rules out the Huntspill one.  Can you get any clues from the names of her children - could any of them be named after her parents?

Very helpful. Effectively the 1841 date of death is misleading and corresponded to a search I was undertaking, mea culpa. In fact I believe that she died in 1847 (burial 9 January 1847 aged 87 at Locking). This would tie in with the 1841 census record age-wise. Curiously the 1841 census result did not show up in my searches on Ancestry previously; however I have now found it and it confirms my previous supposition that Mary PIPE is the widow of John FOORD (dcd 1793) as she is shown as cohabiting with Mary FORD (25) and Charlotte FORD (14) who would be her grandchildren via her son, John FOORD (born 1792) from her first marrige.
This information doesn’t rule out Mary HEMBURY being from Meare as I had initially thought, as you so rightly point out baptism dates don’t neccessarily coincide with birth dates, however her parents married in 1769 which does pretty much rule her out.
Mary HEMBURY from Huntspill was born on or before her baptism in 1755 which makes her death in 1847 aged 87 a problem, as her implied birth date would be 1760.
It rather looks as though I will need to do a bit more digging although having taken your advice to look in the parishes around Burnham, Mark and Wedmore I have so far come up empty handed. The only Mary HEMBURY, baptised 1767 in Wedmore, appears to have passed away young.
I have also found a Mary HEMBURY baptised 17 January 1762 d/o William & Hester HEMBURY in Bristol, but this might be too far away.

HEMBURY and its variants was fairly common around Burnham, Mark and Wedmore so it would be wise to take a closer look at those and surrounding parishes .  FreeREG does not yet have a complete range of Somerset Parishes and of course she may not have been christened as a child but when she was older (one of my own ancestors was christened the day before he got married aged 25).  There is also the possibility of non-conformity and as all marriages had to take place in Church of England churches between 1752 and 1837 - unless you were a Jew or a Quaker - that doesn't necessarily mean that she attended a church.

Where did Mary PIPE die? - your heading suggests 1841 but the Mary PIPE whose death was registered in Somerset in 1841 was only 40 when she died in Bath.

I've just found a Mary PIPE alive on the 1841 census in Lympsham, aged 80 - which does suggest a much earlier date of birth, given that ages were approximated downwards to the nearest 5 years.  Our transcriptions show a Mary HEMBURY christened in 1755 at Huntspill d/o Philip & Mary which you might like to consider.