It seems to me that Sevenoaks was being ironic with his remark about Mc and O’ – see further what he says about denim being French and silk, Asian.
But be da veva is off the mark when he derives Mick from Mc/Mac. The usage of calling Irishmen Micks originates in the common occurrence of the name Michael (my own name, too) among the Irish.
This does not mean the name is exclusively Irish, either. Since it is the name of an archangel, there are forms of it to be found wherever there are Christians (and Jews).
I was named for a family friend who was of English, Scottish and Boer descent, and primarily English-speaking. An 18th-century German ancestor of mine was coincidentally also Michael (different pronunciation).
And bear in mind that the largest ship built and operated by the Scottish navy was called the Great Michael. It was the largest ship in Europe at the time.
Regards,
Mike