Just to add to what Paul and Ian have both said, please note that PRS only deals with Composers, Authors and Publishers, NOT PERFORMERS, and MCPS is similar. I wouldn't necessarily rely 100% what on the MCPS database either, bootlegs do find their way on there, as some less than honest record companies issue what appears on the surface as 'official' recordings and they don't have the necessary licences from the original copywriter owners.
Tim (PRS)
(Ian who's your PRS contact?)