Hello, Paul / Gallus. I'm glad you took up my suggestion to post on Mudcat. I don't know if this is quite what you're looking for, as it's not British Isles, but some countries retain their traditions (as we see happened in England in Lyke Wake Dirge) of paying singers to sing traditional death songs over the body or at funerals. I only wish I could point you to a source that gives details, but my search has revealed nothing for the British Isles beyond what's in the Lyke Wake Dirge you cite in your opening post. But if you do want to go international, you may find these 2 YT videos of interest: Korea and Cypress.