You were right it is a fixed guide Anyway I had the day spare so went for it !
I stripped it fully and DID use expanding foam I checked a few specs and used a B3 grade expanding polyurethane foam. I kept a few "blow holes" clear as it cured and dripped warm water in the blow holes to make sure the foam cured all the way through fast !
It worked better than I could have hoped !!! sorted !
I changed the piston ring, degreased everthing. Made a plastic "oil bottle" spring guide with internal "slip" washer.
Next as no way to get a suitable spring today or make new guide, I resorted to the good old Maccari tar, but only all over the spring guide end!
bit of moly here and there and a smear of some silicon stuff hanging round.
All back together and like a different gun !
Thank you for giveing the tips and causing a happy day !