Hi Paul,
I can help with the 35 piston and the 80 barrel.
Ive a full length Mk1 .22 barrel but it is used, with a little surface rust and the Foresight grooves have been filed down to take a silencer - £30.00 posted
The 35 piston is a new item, I can't remember if it's for leather or Plastic seal - again £30.00 posted
Best Regards
Richard