You say Johns father is shown as a Shoemaker, and Emma's father a Blacksmith. I have it the other way round..or at least I have Thomas as the Blacksmith. I note in Alan's letter he is passing on info gathered by "Roy" your father?"Thomas" (who married Hannah and possibly John's brother) is listed as a Blacksmith on the birth cert I have for Thomas William his son. I am presuming father and son were both Blacksmiths.
I just looked on Familysearch.org, lots of info on Thomas who married Ann, very little on my Thomas who married Eleanor 1814. So many of them! So the crunch is, which Thomas is John who married Emma's father.