Finding parents of John Brown 1774-1845 born Kingsbury Episcopi, Somerset, England?

If your John is the one baptised at Kingsbury Episcopi in 1774, then it is very unlikely that he was the son of Henry Brown. He is recorded as the base-born son of Mary Brown, and Henry Brown and his wife Mary baptised a son Thomas only a couple of months earlier and others earlier still and later. There were three Mary Browns baptised in the 1730s who could be the mother, or she could be from elsewhere, perhaps a sister of Henry who moved to the village when he did, or she could be a widow. Tracing bastards is seldom easy; and the common surname makes it even harder. Your best hope is that there was a bastardy order (a court order requiring the father to support his child) and there are some for Kingsbury Episcopi surviving, see https://www.familysearch.org/search/catalog/830468?availability=Family%20History%20Library . (Not available directly online unfortunately.)

Henry Brown was the only Brown recorded in Kingsbury Episcopi at the time. However some church records are missing and maybe there were other Browns in the village before e.g. in the early part of the 1700s

Hence I am questioning my own search. It could be that the earlier Browns had children that went away, to the Militia for instance, and came back. Henry being recorded as a sojourner at the time of his wedding to Mary Willy does not help.

I will never know for certain as as I said some records are missing but there is always hope that someone somewhere might have dug something up