I have my Bialaddin 315 in bits, my first pressure lantern. The overhaul kit has 6 washers in it. I can see: 2 for the filler cap / release screw. 1 for the valve seat at the bottom of the pump. 1 for the screw cap that goes over the pricker actuator shaft. 1 for the seat where the vapouriser sits. That makes 5. Where does the last one go / what else do I need to take apart?