John L states;
"You have to bear in mind that it costs the site owner money to install, and maintain the hook up points. There are annual inspections and testing, and there are other costs such a council tax, and business rates. On top of these we must not forget that the sites still has to pay for the electricity it uses, and as it is a commercial concern, it does not receive subsidised energy so its cost is greater than what you would pay at home."
Installation costs yes, maintenace, inspections etc are built into the standing charge or combined with the unit tariff and seldom happen anyway. As for council tax etc this has nothing to do with the cost of electric as they would have this tax even if it was not a caravan site. I would assume that ths is built into the price of the pitch, EHU or not. Commercial enterprises pay less per unit for electric than a householder.
To be honest,no matter how you work it out, your consumption for a night would be well below