One of the offshoots of the royalties was 'Blackthorne Records' which gave us (in my opinion) one of the best collections of ballads produced in the Revival (Blood and Roses).
I don't know how much the song netted them; I do know they continued to live in their three bedroom maisonette in Beckenham and to fight for causes such as the miners - can't imagine they ever voted for Mrs T!
Jim Carroll