Regarding Stuart MacGregor: information about him is pretty sparse on the internet.

I assume you’re talking about this guy:

http://www.scottishpoetrylibrary.org.uk/poetry/poets/stuart-macgregor

https://en.wikipedia.org/wiki/Stuart_MacGregor

I can’t find any evidence that he wrote a song (or poem) called “Friday Night Blues.” I’m not saying he didn’t—I just can’t find any trace of it. And I’m pretty tenacious and good at finding things.

I’d be interested in knowing where you got the lyrics you posted.

Has this song been recorded? By whom? When? What album? Any information you can give might be helpful.

Spotify has lots more recordings called “Friday Night Blues.” Spotify only identifies performers, not songwriters. If I had the patience to listen to all of them, I might find something, but I don’t, at least not right now.

This Google search result seems to indicate that the MacGregor’s book The Myrtle and the Ivy contains the phrase “Friday night blues” but maybe not any other lyrics from your song.