The Aris' Birmingham Gazette of 25 April 1825 reported the death of Mr William Mitchell on the 14th April at Fleetstreet, aged 59. There's isn't a corresponding death notice for him in the Birmingham Journal like there are for some of the others in the Gazette of the same date. A possible widow marries Joseph Willday.
If it’s the person I think it is then a nephew was buried 31 January 1822 at Saint Paul's Chapel, Birmingham. But neither Saint Paul's nor the other Birmingham churches seem to furnish a burial for this William Mitchell. Searching ancestry, findmypast (Quakers, non-conformists) and the NBI doesn't turn up a likely candidate.
I've identified Deritend, Saint John the Baptist and Asthed, Saint James the Less as having burial registers missing from the Ancestry collection. Would anyone having access to either those two registers, transcripts of the Roman Catholic registers or transcripts of the Memorial Inscriptions mind having a look for this William Mitchell (also spelt Michell, Muchall, Mutchall)?
Secondly, would anyone know of any non-conformist records for Birmingham that wouldn't be held at the National Archives, are therefore not online, and that cover the period concerned?
