Thank you for your response
DebbieG.

The three letters were found by a researcher in Oxfordshire, I don't know exactly what the 'brief' was because my aunt organised it - pior to that we had been stuck for 25 years, unable to get our CHINA/ CHAINEY family out of Devon. The copy letters we have are all written from Tiverton and are dated June 1st 1816, November 1st 1816 and December 28th 1816. They are full of information so it's exciting to know more may have survived, I would love to know what is said about John! This is from the June letter which does indicate there was ongoing communication
"
I am sorry to trouble you as I do which --- not do Did you but send my pay regular[?] every two months as you promised me and now I have ten weeks pay due to me and I am in great distress for the want of it as I have such a family and no labour at all to do for me nor my family
Neither have I a friend in the world that can help me to a morsel of bread so what I can do in this distressed situation I do not know but this I know if you do not advance me something more than two shillings per week I can not do with it and I hope you will be sure to send it regular but if other ways I shall be forced to send to the Magistrate concerning it or be brought home with my family. I have had a letter from my sister in London and she tells me that my husband is still in a state of --- and no view of him getting any better so he is still in Bedlam so if you do mistrust what I have said you can send for further satisfaction"
Thomas CHAINEY and Elizabeth (nee HATSWELL) married in Tiverton in 1800 and their first child Elizabeth was baptised the same day. We initially wondered if Thomas had got a Devon girl pregnant, gone away with the militia before returning to marry her. Then, like you, I was intrigued by her reference to 'home' which she repeats in the June letter (above) and that she says she has no friends. It is *possible* she and Thomas lived in Abingdon for a while, because the Berkshire Militia disembodied at Reading in 1802 and re-embodied in 1803. Maybe that would be enough for Elizabeth to call it home?
Also there are very few HATSWELLs on the IGI for Berkshire. There are HATSWELLs on the IGI for Tiverton, including an Elizabeth c.1779 daughter of James and Mary. I have not taken this any further as yet.
Thanks again for your interest!