Just a bit of an update/more musings.
I have been having a tinker with a Senior today and delved into the bits bin to try to sort out some linkages for it. I found a barrel and linkage that would not cock the gun and noticed the long link had a stretched hole at the barrel bracket end. Feeling bored, I used a bit of brass from an aerial
and bushed it. The gun still would not cock so I reversed the cocking shoe and that worked. I'll get round to sorting it soon, BUT in my opinion, barring monster springs being fitted or Proper chimpanzees cocking the pistol, I think most Webley cocking problems start with the cocking shoe wearing and then other problems occur as Mr Chimp uses more force to cock the gun, resulting in stretched links, pulled barrel brackets and worn sears.
I tinkered a bit more and fitted a new spring in the cocking linkage. Becasue I have reversed the cocking shoe, it would stick when closing the barrel, which I guess is becasue the edge of the shoe is squared off. I took a half round file and a rat tail file and chamfered it and the underside a little and it is much better oly sticking about 1 in 6 times. Hopefully it will bed in the last bit without attention. As this is on the spare .177 barrel as I am probably going to use the .22 one, I may just stick a label on it so I know in future if I do swap back.