I think I may be able to contribute some useful info. Looking at the marriage record to which TonyV refers, it shows the groom as Joseph McGinley, Master Grocer, aged 38, of 3 Hospital Street in Glasgow whose parents were John McGinley, Farmer and Winifred McGinley m.s. Philbin. The bride was Honorie Meenaghan, a cook/domestic servant, aged 27, usually residing in Morpeth, England..parents were John Meenaghan, Farmer, and Mary Meenaghan m.s. Devitt.
I believe this record has two typos, the first being McGinley which should say Ginnelly, and Devitt, which should say Davitt. I am fairly confident in saying so for they all relate to me and come from a Townland called Rinnashinnagh (now called Foxpoint) near Barnatra in Mayo, Ireland.
Joseph was born on 8 Dec 1875, Honorie 1886. Joseph had (at least) 4 siblings....Mary, Ellen (Ellin), Ann and Martin.
I have evidence the registrar in Glasgow either wasn't very literate or spelt names phonetically as the name said in a strong Irish accent sounded to him. (Add an um before Ginnelly and you can imagine it sounding like McGinley.) This said, it may be he was happy to have the Mc added to his name so it sounded more Scottish in an effort to overcome the rampant discrimination taking place against the Irish at the time. I doubt it though for they were both back living in Mayo by January 1915 when they had their daughter Mary. (They also had other children including a son called Michael Ginnelly). Hope this helps