This was a group of session musicians formed to be the resident band on the pop TV programme Oh Boy! shown on ITV in 1958/59.
Hoots Mon was written by leader Harry Robinson and reached No 1 in Britain in 1958. It was notable for being one of the first rock and roll songs to feature the Hammond organ, played by Cherry Wainer. Jazz saxophonist Benny Green played on the recording but I am not sure if he is on the video.
Cherry Wainer was one rocking lady, sadly no longer with us.
There’s a good section about her and “Oh Boy!” in this documentary, starting at 27:30.
https://www.youtube.com/watch?v=kV5bgsYCNPk
She says that “Hoots Mon” was the first instrumental number one hit record.