When I wrote that stuff below about Keith Relf (which I stick by) and Mick O’Neil, it was based on my memory of something I heard once, on a live TV show 50 + years ago
Now I’ve found a recording, I’m not so sure! O’Neil did sing with them but it’s a bit ordinary – rather like the Blow-Up sequence it’s typical Yardbirds R&B; an instrumental group, with a bit of singing interrupting now-and-then. I reckon perhaps they improved a bit with those pop/psych singles? Mind you they were booked for the Birdcage and never came, so sod’ em.