Personally I wouldn’t get gas from there, gas price ok, but look at the postage, £30! Then postage to sent it back possibly & another lot for the full one. You want somewhere local so you can change it easily, it’s bound to run out just when you need it for this weekend. Look at Hobbygas, Adams gas or SGS, with SGS you get a rebate on your deposit through the forum of I think it’s £20, but for me the deciding factor would be ease of swapping if the price was similar.