Shelley (a.k.a. Jan Lynch) and the Big Valley in 1974

In this photo from Entertainment News, 16 year old Shelley, replaced Frank Coll (Brian's brother) as lead singer with the Big Valley.
Back row l to r: Shelley (vocals), Jimmy Smith (bass), Tony Fox (keyboards), and Aiden McGuigan (guitar).
Front:  Michael Lynch (sax), Martin Coll (guitar), and Seamus McNeil (drums).