Thank you for all your replies.
I bought the gun June last year via Harry Preston, it came with a green transfer port giving me 11.1 ish on the chrono that was the highest it would go with that port using JSB 8.4 Was advised to put a black transfer port in as it would shoot sweeter and I could try lighter pellets at a higher speed. I haven't really got on with the lighter pellet, takes too much wind...but at the moment the gun when filled to 200bar is doing approx 11.4fps with JSB 8.4's. The only other thing I did was to take the grub screw out to make it nearly free floating.
I'm not at all technical but looks like a chrono session is the next thing to try. I have a feeling it may have had the problem from the start. Then maybe back to Harry to sort, hopefully within warranty.
Good to hear from you, we're both fine, Clive's more into his cars and bikes at the moment, still occasionally gets his springers out and beats us
thank you for your kind offer, I'll see what the chrono says.......