I have just purchased a 7kg butane refill of calor gas and been charged £14.99, at the same time I purchased a 13kg butane refill from flowgas at £12.49. I asked the calor dealer why calor gas was so expensive, £2.50 more for almost half the gas compaired to flowgas, he said its because carvaners use it, the bottles fit into the gas lockers easyer. I spoke to flowgas and asked the price of their 7kg gas, they replied £10.41 for the refill, £15 one off deposit for the bottle. Guess were I will be going next time I need a refill.