hi all my father in law has had this gas oven for two years , fitted by pro gas firm . for a while now it doesnt seem to get very hot . actually i dont think it has ever beeen that hot .you turn it to gas mark 9 and after about an hour water hardly boils in it . the flame burms a high bluey and red and orange colour and after 4 hours with it on gas mark 9 it never goes down always high . we have been telling him to get gas firm out for ages but he says its nearly new it should be ok. so whats the problem ??????/ he is an elderly chap and recently had food poisening which was found to be from chicken , and as the oven doesnt seem to get hot could this be cause? how can a 2 year old gas oven not work properly ? what could be the cause of this?