TURNBULL - James and Richard this time please in 1841/1851

[ggrocott]

Looking for James Turnbull and wife Elizabeth who married in 1792, so presumably born about 1770, and Richard Turnbull and wife Hannah who married in 1801, so presumably born about 1780.  I believe they may be brothers.

Both couples were married in the London area, James and Elizabeth at St Martins in the Fields and Richard and Hannah at St George Martyr. 

Both appear to have baptised children at the Wells Street, Scotch Church, St Marylebone although James and Elizabeth also seem to have bp children at St Giles, St Mary's Marylebone and St Andrew's Holborn (17 children in total between 1793 and 1825!!!!! and only two repeated names!)

Any help much appreciated.  I have a theory about the relationships but now I have to prove it!