I spoke with the PRS about the MCPS recently… It sounds like it’s only worth joining if you publish your own tracks, and I don’t think you can back-claim any royalties from before the date you join anyway.
Hi Mark, it seems to be standard performing royalties, as far as I can tell. You have 11 results, although some are collaborations. I thought other PROs would have a similar searchable database of unclaimed royalties, but I might be wrong.