Sorry Annette, I have no idea where the Louise came from except that my husband was talking to a neighbour named Lousie as I was typing. I do apologise.
Re-reading my first message and I see why you should think that I had Thomas as a name for the father of both Josephs. It should read "but is another man named Joseph living ......" So two Joseph Farrers in the same area at the same time.
As I have come to a shuddering halt on Joseph's parentage (as you say a couple of possibles but nothing confirmed) I am now trying to trace the descendants. Joseph himself died at Holme Hall near Mansergh and his children and grandchilden appear to have settled in the immediate area "just over the hill" from Grayrigg. The Sedbergh registers have Farrers back into the 1600s so I may end up doing a local one name study at some point.
I am now concentrating on Joseph (1761 - 1843) and his children and grandchildren.
It's not the first time I have found a will that drives a horse and carriage through assumed family relationships and people don't always react well when you query their findings.
Wills and Admons are (in my opinion only) a much under utilised resource - and very cheap to get post 1858 copies these days. If there is a will it really helps to pin down connections and can also raise other queries.