Malcolm, in your Saturday 09 June 18 22:51 BST (UK) Post, you mentioned George Boynton Leggett. I didn't notice that, but he died in childhood. He can be disregarded.
You also mentioned the Jane born in Newfield. That is about as far out of Durham City as Tudhoe is, so again I can't see how the Jane with George Leggett could be born there and describe herself later as born in Durham City.
Throughout the 1890s and into the 20th century Jane seems to use whichever surname she fancied at the time. Even in 1900 when her 6th child, my grandfather, was born she used the name Thompson.
On the marriage certificate for Jane's marriage to Henry Thompson she lists her father has Edward Adamson, engineer, and herself as spinster. I do accept that for a young woman to be still single, spinster, at 29 in those days, is a little bit unusual, but perhaps she was just choosy!
Martin