I learned Supermarket Wine from the singing of Jim McKenna in St Andrews in the Square in Glasgow around 2003/2004. Jim was a tremendous singer for many years and when he put his mind to it, a great songwriter too. He had been unwell for some time, but still appeared from time to time in the Uisge Beatha on Woodlands Road on Sunday evenings. A real fighter! I've just heard that sadly he passed away very recently. Here's a Youtube link to him singing Supermarket Wine in Glasgow in 2008.
I'll miss him. So will a lot of people... RIP