Nothing overly major. I was wondering why I couldn't get the valve port/ grub screw hole to line up where they should, the valve just wouldn't push in far enough. Turns out unlike most (or so I thought but I'd stand corrected) mk2's mine doesn't have the recess for the oring (the small one on the valve tail).
Which isn't the end of the world, I'm guessing I can just remove that oring from the valve and It might seal anyway.