I might have a solution, I thought that the instrument dimmer switch (next to headlight control switch) had three settings. In fact, it only had two, I had it at the highest setting, thinking that it was just the brighest setting for the instrument cluster when it was a 'stay on permanently' setting for the interior light. This means that when I closed the door, the interior light AND ignition barrel light (the work in unison, btw) would stay on until I removed the fuse. I finally resorted to the owner's manual and realised my mistake. It may be possible you may have accidentally done the same, however your interior light globe is not working, leaving your ignition barrel light on only.
Just a thought.