Complex sentence: The backing band was made up of members of Clover, but they were uncredited on the original release due to contractual difficulties; some early publicity for the album identified the backing band as "The Shamrocks".
Split into simpler sentences: The backing band was made up of members of Clover. They were uncredited on the original release due to contractual difficulties; some early publicity for the album identified the backing band as "The Shamrocks".