Interesting question Bill. Edinburgh has so much religious history--John Knox and all that--and yet, I've not been to a church service in Edinburgh. I have been to St. Giles and it's interesting. I've been to so may abbeys in the Borders and elsewhere. I've visited my cousin's very stark church in Longhope on Hoy, but no services. Your post made me look up to see what the Internet had to say about historic churches and this link came up. I should have remembered Grey Friars.
When you think of church--the kirk--in Scotland one thinks of the Presbyterian Church, but it's called the Church of Scotland. I had to look it up to clarify this for myself, and I thought that this statement from Wikipedia helped. "The Church of Scotland is Presbyterian in polity and Reformed in theology. The most recent articulation of its legal position, the Articles Declaratory (1921), spells out the key concepts." And here's the link to the website. And then there is the Free Presbyterian church. Click on their link on Sunday and you'll be told that they are closed for the Sabbath.
So, Scotland is a different place for church than the rest of UK or Europe. Hopefully, MC or Unclegus will comment.