Maybe he wasn’t so well-known outside of Scotland, where he was a regular visitor to many folk clubs and festivals, though among the many times I saw him live, I would include Sidmouth Folk Festival. I rushed in almost late, found the only free seat in the front row, right under his nose. When he asked what people would like at the end for an encore, I suggested “Niel Gow’s Apprentice” which he sang.
He collaborated very successfully with many other musicians and artists, from symphony orchestras to smaller groups (McFall’s Chamber) and poets (Liz Lochhead).
There are plenty of videos on YouTube to catch up on him if you’ve never heard of him.