Thanks for responding Averil. I too found the marriage between James Coulthard and Margaret Guy and I thought I'd made a breakthrough. Unfortunately James and Margaret had her mother living with them in 1951 and her name was Jane Robinson, born 1774 in Westmorland. Someone did suggest that maybe Margaret or her mother may have been married before, hence the different names, but I have never found any such marriages. I keep coming up against these brick walls but I'm sure I'll get there in the end. Thanks again anyway.
Regards
Gerry