any other ideas please??
Just found the gas valve leaking as well,not too happy.....
A leaking gas-valve isn't good news, it's rather unsafe. I would empty the tank outdoors and contact the dealer you bought it from. Do you mean the filler-valve or regulator valve?
Assuming that gets resolved, you could try filling it up as I do, use 180ml or close to that and run for 20 minutes (steaming). I'm really not sure if the unreliability of the gauge is peculiar to my engine or it's a case of "they all do that, sir" i.e. not well designed.
It's not a cheap engine so they really ought to resolve your problems!