Why arent the babeshows on NTL?

as the title says, how come there only on sky?

I think it's a purely economic decision. I know for certain there are two are on freeview and a few on freesat. I couldn't speak for Virgin, but considering the slump in customer take-up for NTL, it's entirely likely that the channel operators aren't willing to spend the cash required for extra broadcast licenses etc., without a substantial base of potential customers to draw from.