I have a lodger his rent includes all bills, however I went on holiday for 2 weeks and on my return he presented me with a £25 top up bill for the gas which he used for heating when I was away. I told him there is no way I am paying for the gas he used when I wasn't here. He says gas and electric is included, but my argument is that if I was on holiday the gas would not have been used so he has to pay it. AIBU?