I've just logged back in and I'm amazed to see all of your replies - thank you so much! I've not been getting email alerts, I'll check my settings.
I now know that Christina Moore and John Roberts married on 11th March 1924 at Somerville Memorial Church, Keppochill Rd, Glasgow.
I still don't know for sure when she came to Glasgow and my dad doesn't know either. Not a great deal to go on.
I'm going to read over all of your replies as I see there are links to census'.
Thank you so much for taking the time to look into this for me.
Dathai - you asked about St.Francis at Cumberland Street, Gorbals. I'm pretty sure this is where my dad married his first wife. Someone in my dad's family definitely married there, I'll need to go through the family tree and check.
My dad lived in the Gorbals for years, but the name Andrew McGrath doesn't mean anything.