Hello, I hope the following assists you.
As this is a later Puma the interior light is controlled by the GEM, usually the interior light dims as it turns off rather than the earlier Puma where it was a straight on/off controlled by a door switch to earth.
As the light isn't switching off this would point to a fault with the GEM especially as no door ajar warning is showing. Try disconnecting the blue GEM connector, this is near the fuse box in the car, this would eliminate a short in the wiring between the light and GEM, if the light stays on this would indicate a short in the wiring, if the light goes off this would indicate a GEM fault. The connector you need to disconnect is shown below.
I hope this helps but if you have more questions regarding this let me know and I'll reply as soon as I'm able to.
Many Thanks but where is the GEM located exactly? I have never seen an internal fuse box thanks.
the GEM is on the fuse box inside the car, on the right side of the dash low down near your knees there is a small panel that pulls off to reveal the fuse box, there are 2 screws to remove the fuse box, it then unclips and pushes away from the dash, you then spin the fuse box and the GEM is on the back.
Below shows the fuse box with the cover removed.
Let me know if I can assist further.