ah i'm not from the UK so I don't really know what you mean. But i think you are asking how much it would cost to run two 600w hps lights. Well, 2 X 600w = 1200w, then 1200w X 24 = 28.8 (Kilo Watt Hours). The price of energy in most places is somthing like 0.09 $ Canadian (or similar conversion). I found a site to help you, this should help you determine amperage too. which is super important if you don't want to burn your house down.