Just seen a brief feature on this on BBC Breakfast.
The group is called By Chants (I think), and is the brainchild of a chap called Crispin Thomas, a football poet. They interviewed a couple of the singers - not Ben sadly - though they did say 'some members of G4' were involved. There were seven guys in the group, all kitted out in football shirts.
Apparently it's something to do with a vote in Nuts magazine to find the best football chant.