I've been puzzling over this for some time. I finally contacted Hebden Bridge History Society and sent them the required payment - £5.
http://www.hebdenbridgehistory.org.u...-documents.pdf
This morning I have received scans of the two wills.
I'm over the moon - despite my scepticism the Thomas Jackson will is that of my 4x-great-grandfather.
There was also another son. The icing on the cake - his son Henry was indeed schoolmaster at Heptonstall. My 3x-great-grandfather Isaac is mentioned.
Now I can ask for scans of the other documents.
I had asked the Archives and the Borthwick Institute about possible wills for this family and they had none.