Thanks for the advice, I've located the problem, it is the actual fill adaptor ( I borrowed a new one and it worked perfect )

Paul.

Advice please, I've recently bought a second hand S200mk2 as I've heard so much about them, it has the T-bar filling adaptor and when I went to fill the gun it was leaking from the base of adaptor, I've replaced the two rubber seals at the end of the cylinder but it's still leaking and will not fill...