Hi Doug,
Checked again, and I made a typo mistake in my earlier post.
Richard and Alice son Archbold was baptized at Burgher Secesssion Chapel, North Sunderland, daughter Margaret Richard was baptized at Clayport Presbyterian, Alnwick. Not the other way round.
Margaret Richard was definitely baptized 27 Feb 1817. pm me your email adress and I'll send you a copy of the original record. The page header is 1816, but the records change to 1817 half way down the page.
FreeReg has Richard Mitchison burial 23 Feb 1817, Embleton. Richard Mitchison of Stamford, age 28. Usually very reliable, but I haven't seen a copy of the original record.
Cheers,
Alan.