The gas won't be much because cooking/HW doesn't use much compared to CH. However �7 doesn't even cover the average standing charge. You could roughly work it out yourself. Prices do vary across the country and are different from each supplier, but if you used 14p per day fixed charge for gas and the same for electricity, then priced at 8p per Unit for the electricity on your own meter readings, and 80p per Unit (100cubic feet) on your gas meter readings it should give you a rough idea if its OK.