There are wills of what I believe are JSD's aunts which may be of interest for a little background, though you may well have seen them already.
Start here
http://familyrecords.dur.ac.uk/nei/data/simple.phpand put Donaldson into the search box, select them all and look at the results. From there you will see links to the images of the wills etc on Family Search.
Ancroft is mentioned 3 times. I had a quick look at the wills for Margaret and Elizabeth who seem to be the aunts of John Strangeways Donaldson and he was a beneficiary. Elizabeth's will was written in April 1828 and mentions her "nephew John Strangeways Donaldson, son of my late brother, John Donaldson, now residing at [not too sure what the specific place is] in the County of Essex. So if it 'is' the JS Donaldson then he had been in the south of England for quite some time by 1851. His daughters, Margaret, Margery and Ann get a specific mention in Elizabeth's will.
They were the only two I looked at, there are other Donaldsons but you'd need to look and see if they are relevant to the people you are looking at.
I find the writing in these old wills, coupled with the flowery legalese type language, makes them difficult to read/take in from the image.
If I have one that I am particularly interested in, I find it helpful to type it out word by word and then split it up into little bits. For me, that helps to make sense of it.
Boo
