I think I have cracked it. I didn`t spot it before
When Mary was found at the boarding school in 1871, there was also a Fanny Edmunds aged 10 also born Middle. There was no relationship given but now it seems that they were sisters.
Unfortunately Fanny was born Sept qtr 1861 so doesn`t appear in the census. Again this is before Richard married Mary Edmunds in 1867.
I searched for a death in the area and found this.
Deaths Dec 1865 Ellesmere, Mary Edmunds
I looked for a marriage between the death of Francis in 1851 and the birth of Mary in 1859.
There were only three with a spouse named Mary.
This is the one, but not where I would have expected.
Marriage 2 Nov 1857 Chelsea Holy Trinity. Kensington and Chelsea . Both of full age.
Richard Edmunds widower farmer, residence St Martin’s Square City of London.
Father William Edmunds farmer ( same as his marriage in 1867)
Mary Groome spinster residence Chelsea. Father: Edward Groome
I then checked the 1861 census .
1861 Smethcote Baschurch.
Edward Groom 40 unm farmer b Hadnall Shrops
Jane Groom sister 42 b Hadnall Shrops
Mary Edmunds sister married, visitor farmers wife 39 b Hadnall Shrops
In 1851 Mary is described as born Middle, this is too much of a coincidence for it not to be the right one. Living in Shatton, Bashurch.
Not found in 1841.
I am 99.99% sure this is the second marriage and this Mary is therefore the mother of my Mary and Fanny.
A further clue is that Fanny married William Robinson in Mar qtr 1884 Ellesmere, Shropshire.
and here we have a William Robinson . I think from looking further back that the Robinsons are linked to Richard`s current wife .
1871. Middle Farm, Middle. Ellesmere,
Richard Edmunds 65 farmer 450 acres, 6 men 3 boys.b Montgomeryshire
Mary Edmunds wife 30 b Montgomeryshire
William Robinson nephew 19 assistant on farm b Montgomershire
Sarah Edmunds daughter 7 b Staffordshire
Now, why on earth did the marriage take place in London