Sorry for building your hopes up, but the Margaret Brown baptized at Warenford Presbyterian in 1823 is not the right one.
A marriage at Alnwick St. Michael, 21 Nov 1850.
Edward Potts, Bachelor, Drainer, of Denwick, and Margaret Brown, Spinster of Alnwick. Grooms father - John Potts, Labourer. Brides father -William Brown, Joiner.
In 1851 census :
Yard of No 13 Bailifgate, Alnwick,
Edward Potts, head, 23, Drainer, b. Denwick,
Margaret Potts, wife, 26, b. North Charlton,
So the search goes on for your Margaret Brown.
To recap on what we know about her :
Born about 1825. b. Clattery (1851 census), b. Ellingham (1861 census), b. Warenford (1871 census), b. Clattery (1881 census), b. Clattery (1891 census).
From her marriage cert to James Beverley, her father was John Brown, Coal Miner.
She married Thomas Dixon at Lamberton Toll in a cross border marriage. He was from Lancashire so unlikely to be a Scotch Presbyterian, so its likely either that Margaret was a Scotch Presbyterian or that they married there to avoid needing parents consent.
Alan.