cheers chaps, ive removed the brass fitting and they both are 3/8bsp. The first one came off easily but the second was on rather tight! isnt it always the case. Ive also got a smaller bottle, similar to a sodastream bottle that i think is out of a water fire extinguisher, so might put that in as well (that also had a brass fitting onto a 3/, so might have all three in!
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