Nope, its not like that one. Its a standard 749/999 cap. If I could get it open, I could get access to the bolts and take it off, which would make life easier. But its locked!
remove pump, reach up inside with a phillips screw driver and undo the two small screws on the bottom of the tank cap, this will allow the catch system to come away from the rest of the cap allowing you to open the top part. Keep a eye open for the odd spring etc.
Does that work with the 748/9** tanks as I know another DSC member with the same problem after he bought a trackday tank but the key hasn't materialised ....
yes Pietro it works with the 748/916 tanks, I've done it on the 916 tank but not the 999 I'm assuming its the same I'm sure Khuram will soon let us know if i'm wrong