Thanks for the replies guys. I was considering getting you guys to do it (Andy, that is) but I think the shock is just a little low on gas and doesn't need a rebuild yet (when I eventually start taking it to track days I'll be keen to get the suspension properly done). Although the refurbishment works to as-new condition is quite enticing! I'm mostly just wondering the best way to get the cap off and best way to add a valve. I just don't want the end of it to get blown apart when under pressure. I was thinking to just getting the valve welded on (My friend is a pretty good MIG/TIG welder) but just wondering what might be the best plan of attack.