"glad you mentioned the marriage"
"although he and Margaret were married in Newington, Edinburgh where she lived, presumably with her family"
All extra info. is very helpful for cross referencing especially middle names/initials, maiden surnames, occupations, addresses, witnesses etc.
It may be possible to find out through the VRs who Margaret was living with if you provide the address at the time of marriage?
I'm assuming you haven't found their deaths to date?
What were the names of their parents, with mothers' maiden names?
If they moved back to Scotland & died here, after 1973 their mms will show on the index if it was known to the informant?
Annie