It sounds like TB was rampant in those times as according to William Pywell's b 1804 (Emma's father) death cert he died of the same.
Some time ago I made contact with the only Pywell in the NZ phone directory. Quoting "My grandfather was Archdeacon Barron Pywell from Dunedin. He was sent from Melbourne by the Anglican church to set up the Anglican church in Clyde in central Otago. His father was from England and was a school teacher and went to Australia to carry on teaching." He wasn't sure about more details but his niece on Brisbane maydo. Don't know if rings a bell for you.
I would be very interested in receiving a copy of Peter's list please.