Good evening Steve,
thanks for your prompt and full reply.
Thanks too for confirming the date was 1838 and for posting the actual Burial Record. I note that this was actually in St Briavels - the reason I posted the 1796 one was purely because it was in Hewelsfield, which is what you told us in your original post. Here's the Record transcription from this site's database, I see now that you meant he lived in and quite possibly died in Hewelsfield, but not buried there.

Record_ID: 333975
Entry_Number: 422
Year: 1838
Month: Jan
Day: 15
Surname: WILLIAMS
Forenames: Thomas
Residence: Hewelsfield
Age_at_death: 59 years
Officiating_Minister: J Gosseliu[?] Smythies Curate
Event: Burial
Cause_of_death:
Memoranda:
Notes:
Register_Reference: P278 IN 1/19
Page_No: 53
Parish_Chapel: St Briavels
Soundex: W452

I have no reason to doubt the record clearly states 59 years. However, even in Burials during the late 20th Century we see cases where the true age of the deceased is actually a few years different from that which their family, friends, etc believed to be true, and so reported to the church Minister for the Burial Record. There were also some cases where Ministers just mis-heard the reported age or just acccidentally wrote down an incorrect age. Now go back to 1838, when most rural people's lives were not governed by time or date as they are now, indeed few had regular access to clocks or calendars, or regular reminders such as newspapers, and maybe couldn't even read or write down what their birth year was, so it was quite likely that in older age they don't know their exact age, or that the reported age at death might be incorrect; especially as in those days the Forest accent was far stronger and more difficult for the Minister to understand before recording what they thought they heard. Even if a person did keep good memory or records of their actual age, we still see plenty of examples on the Victorian Censuses where people deliberately quoted incorrect ages, either wishing to be "younger" when in their late 20s, or older when they were elderly; there was no government, DHSS, NHS etc databases to compare against after all. So yes, I agree that your 1838 Burial states aged "59", but I suggest this is still only a useful approximate guide and nothing more.

Yes it's a great that you've found Thomas' Will, an interesting and very useful document. If that survived I wonder if there are any other records relating to him which have also survived ?. Was the Will in the local Archives, is there more waiting to be found ??

No, I'm afraid I'm not in any way linked to the family. I'm just a fellow member of this great forum who's trying to help out with your query.

I've re-searched this site's PRs and also FamilySearch site records for him, but no real success. As you'll know it's a very common name in the area, there are several possibles born in and around 1779.

You mention his daughter and husband. Have you fully researched their lives, are there any clues there as to Thomas's origins ?.

I've tried a quick search for him within the BNA old newspapers site but without luck, ditto William Wargan of Brockweir.

Hopefully we can move this on a little further in the next few days, but at the moment I'm unsure how.

???
ttfn Jeff.