This is a
government statistics site where you are supposed to be able to look at such things as cost of living, salaries etc. but I must say I haven't managed to find this particular area yet. Perhaps you will have more success.
This is another site where they show
various cost of living expenses but it's more for consumables only. Perhaps it will help you to build up the picture if nothing else.
This
little toy might help you calculate how much electricity and gas you'd have to pay.