Just been to our local recycling centre as advised by motorhome dealer to see if they had a second 6kg propane cylinder. Found one and took it to the local campsite to refill to be told it is half full. Now I am a bit worried about using it as don't know it's history. Should I use it or just replace it as I presume that they're safety checked when refilling?
I'm surprised we haven't had a 'Captain Safety' on spouting that GAS BOTTLES SHOULD NOT BE USED WITHOUT A EUROPEAN SAFETY CONFORMITY CERTIFICATE! And that THE SAFETY OF YOUR FAMILY IS NOT WORTH SAVING £10 blah di blah.
Not a lot can go wrong with a gas bottle. The fact it is still half full suggests it's not leaking. Providing it is clean, not full of rust and your connector fits properly with no leaks then it should be safe to use. As already mentioned, bottled gas is too expensive to throw away.