For now, if it were me, I'd just take the little screw out of the collar the cap fits on to. The cap can stay locked, because when you twist out off it'll unscrew as normal but will have the little collar still attached.

Or as you say, you might be able to rearrange the innards of the lock to accept the door key.

I didn't follow Terry's reply. I should have asked for more clarification. From the photo it appears that the screw holds the collar to the rear wing. I had never noticed the screw until now (or never paid any attention to it).

So all I need to do is remove the screw on the collar and I can remove the fuel cap even if it's in the locked position?

Yes, because the cap is locked to collar, not to the fill tube...

Sorry, my mistake, I should have explained more clearly ....the screw holds the collar to filler tube, not the rear wing..... but yeah, if you remove the screw, the collar and the cap will just twist off as one peice providing that the cap is locked onto the collar, it acts just like a normal [standard] fuel cap, it just looks like a locking cap.
T.

Thanks I will give it a try. I've been working this past week so I haven't had a chance to look at it. I'll check it out this weekend.

Thanks guys! I removed that screw and the cap functions as a non locking cap now.