I think you need to watch the credits of the show.
Tara Mc Donald (seated on the left) is a very respected session singer and top line writer. She recently had a huge hit with My My My with Armand Van Helden. She often sounds like a black American diva which isn't bad for a white girl from Kent
Tommy Blaize (seated next) is a session singing legend who has just featured on the latest Basement Jaxx Album. He featured in the first series and the tie in album from series one
Priscilla (I think, seat three) i don't know a lot about but Craig Revel Horwood complemented her by name on her very first show
Lance Ellington has been a session singer for years and features on numerous PWL tracks as a backing vocalist.
I think they do an amazing job jumping from one extreme of style to the other within the same show. There is the very occasional track that is underperformed but these are few and far between. The singers haven't changed much for at least a couple of years. Ther has been loads of continuity in this aspect, with or without Laurie Holloway
HCG