i am building a lento on the side of the bungalow now in the way is the flue from the boiler now i was just going to make an extension to the flue out of some tin and exaust it through the new polycarbonate roof ,but have been told that is illegal is this correct or not i was told it had to be ouside with a clearance of 600m/m all round and as the boiler needs repairing i need to get this right or no one's gonna fix it