Hi, I'm looking for a replacement filler cap for my Mk3 R-Reg Astra. The original was the type that had two metal lugs that held it into place and was not lockable. (The outer cover locked with the central locking). In looking for a replacement, there seem to be a lot arround that have a screw-in fitting(some of which are lockable - which would be nice). Are the two types interchangable, or is the fitting on the car different for both. (I'm guessing that this is the case, but would like confirmation). Regards, Chris.