I must be bloody lucky where I live I put my bottle in for checking at APS Marine, they did the research and found it was leaking (damned thing was empty after filling rifle once) They didn't try to push things but when I said it were getting close to retest date Brian said "now you've mentioned it why not get it re-tested while it's away". I recommend APS Marine to anyone who is in need of divers air or air gun air. A thoroughly nice firm. Just outside of Salisbury.