Thank you both for your help on this. It seems like James' movements are a bit of a mystery. A couple of additional questions – is the inventory list from Margaret Maddrell's will available anywhere and secondly, is the 1992 article on the Callow family available other than in the MNH Library as I'm researching this from Australia.

Bruce, like you I'm assuming that Ann was the Ann Collister/Callister Maddrell who was christened at Rushen 16 Dec 1770 and died at Rushen 29 April 1744 aged 73 – the ages would fit more than the other Ann Maddrell who died in 1832 aged 58. If you want any information on James' descendants (through the line of his eldest son William b. 1787), please let me know and I can forward you as much as I have – which is still very much a work in progress.