Thanks all for replies, much appreciated. Sorry about the late reply but I have been away working for a few days. Apologies.
To answer the questions, he is listed as Owen on my GGF's marriage cert too, and his occupation is listed as a carpenter. They were married in RC Church but I don't know as yet whether my GGF was baptised as RC or whether it was his wife who was RC? Because as I stated, I can find no record of his parents marriage or his birth? My GGF John McCall is listed on the Scotland 1901 census aged 37? along with his wife and children. I have also searched the different variations of M'Call and also the spelling of Owen/Owan but didn't find anything. I found an Owen McCall on the Griffiths valuation site, but can't verify as the dates seem a bit early? I've also checked to see whether there were any other children born to his parents but didn't come up with anything either.
Thanks again for replies.