These people are "the other half" of the original HSCC (Hindley Street Country Club). They all used to be part of the HSCC collective, but then Con Delo (founder, bass player and band leader of HSCC) had some sort of falling out with Darren Mullan (co-founder and original pianist of HSCC, founder and keyboard player of SingItLive — on the far left in this video) and Darren went his own way, taking a number of the original musicians with him.
It all happened in quite a short time span, and nobody really knows what went wrong between Con and Darren. To the best of my knowledge, neither of them has so far spoken publicly about the split :noidea: