Because he'd sing with a birkenhead accent...not really
I'm pretty sure its not him, he was one of those saturday cinema child actors not a singer - only when he had a TV career did the music industry crank into action for their crap pop records business. y'see its all business. I asked Andrew King about this in the mid-80's and he seemed to think it was a a contact through EMI Abbey Rd, they'd know where to find boy soprano's.
Me and Mr King agreed that their 2nd album (which he produced) was their best recorded work