Don't know about the children, but there is a ships voyage which might be Stewart & Mary.
Departing Southampton on 13 July 1954 on the "COLUMBIA" to Montreal was...
Stewart Russell, aged 32 Toolmaker
Mary Russell, aged 31 Housewife.
If you already know that Stewart Russell's occupation was Toolmaker, then I think this might be him and his wife. I saw this on Find My Past.