David, I was reading all the posts and think you writing a book is a great idea as I've loved your sidebars to your Bens posts.
I kept thinking, I could never give you any info that would help, and for about five minutes I thought you hit on something I might be able to help with. My brother trained at Barmulloch College. He worked for Howdens in Kinning Park and did day release at Barmulloch (bussed it there). He received his City & Guilds there (twice, but you weren't allowed to get it twice, so his friend was awarded it the second time).
I believe it was an engineering degree, but I could check with him and ask what exact courses they did there. He was there in the mid-60's, so you would have to check if it was there in the 50's. Cancel that thought. I googled and it only opened in 1964, so it's out of your date range. Oh well, for a few minutes I thought I had something interesting for you. I'll keep trying. Good luck and let us know when you finish.