Oh goodness. Thank you Rosie. OK, this gets even worse. Here are the GRO results for the children ....
Daughter Catherine age 10 in 1851 - her mother's maiden name was DRYDEN, from the GRO site
MACDONALD, CATHERINE DRYDEN
GRO Reference: 1840 J Quarter in DURHAM AND LANCHESTER Volume 24 Page 86
DONALD, JAMES EDWARD DIMOND Order
GRO Reference: 1843 J Quarter in STOCKTON AND SEDGEFIELD Volume 24 Page 271
MACDONALD, ROBERT DIAMOND Order
GRO Reference: 1845 J Quarter in STOCKTON AND SEDGEFIELD Volume 24 Page 263
MCDONALD, WILLIAM MONGHUN Order
GRO Reference: 1847 J Quarter in STOCKTON AND SEDGEFIELD Volume 24 Page 283
I now have absolutely no idea what I am looking for. Thank you all for your help anyway. What a nightmare.