How do i get the old piston seal off? does the top pry off, or unscrew as local model shop thinks. IWas bit unsure on the condition of the carbon bushes and thought they would be best place to ask.

Get hold of seal with a good pair of pliers and pull it sideways or cut it off with a Stanley knife. Top of piston is levered off (carefully) after you get most of old seal out of way. Remove any burrs, fit new seal and press retaining ring back into position making sure seal is gripped all the way around. I always put a few pop marks around ring to make sure it cannot come off. Which local shop did you go to the butchers?

Cheers wammers. Gent as always. Not quite butchers.