Hi there,   I'm hoping someone who uses one of these regularly might be able to help. I've had one for a year but only use it occasionally, so it goes a few months at a time without being used. The problem is the self stopping spout on the petrol, which doesn't stop, therefore making a lovely mess (worked fine to start with though). The issue is that it doesn't 'pop back' properly, and gets jammed a few mm from closing. I bought a replacement spout which also worked fine at first  but