If they are pretty much all overcharging how is publishing a list of all their overcharged prices going to solve anything
I know I keep going on about the two garages by me but no more than 300 yards up the road from one is a BP, it's 8p a litre more expensive, even being right next to be cheapest petrol station for miles and miles and miles doesn't put the price down
Publishing a list of live prices will achieve absolutely nothing.