Original model 5 ( grey grips .22)

[Geezer]

You do need to take apart the entire trigger mechanism (and remove the barrel) to get the piston out.

It takes time, but isn’t particularly fiddly. I don’t recall anything flying off into the blue yonder when I last did one.

It helps to take lots of pics as you go along.

[charub]

Thanks for the help so far everyone.
Protek supplied me with a new piston and breech seal, which have now been fitted - all is working as it should.
I have now stripped it back down to component pieces ready to send to Shaun at ISP for a re blue.
Couple of questions regarding the front sight -

It is complete but in a poor state so would like it re blued also. Has anybody successfully removed the plastic shroud that covers the hood in a manner that can be re used? (Can’t imagine I could replace it)

Is the circlip that the screw holding the front sight onto the dovetail the same size as the one used on the rear sight? - I can buy the rear one from chambers, but they don’t show the front

And lastly, was the lettering on the cylinder highlighted in white originally?

Thanks.