I put this down to possibly the need to tweak the convenience ECU, but with my new vRS internal roof light fitted, I get this

Switch set to all on = all on

Switch set to all off = all off

(fine up to now yeah )

But switch set to turn on with doors - With doors open, it lights up (OK right ) but with doors CLOSED, the red lights on the bottom of the doors stay ON, and all three bulbs in the light unit have a very slight glow to them.

Any thoughts?

?? back-flow of current - perhaps check that the door lights at the bottom of the doors don't have another separate supply of current coming from elsewhere.....

disclaimer: forgive me father for I know not what I do......

Weird that those door lights are out though, when the internal light is on as it should. It's almost like whatever makes the red door lights switch on and off is reversed to what it should be. As for the 3 bulbs glowing lightly when the doors are shut? Might be related.

It's not the delay thing where they only turn off when you turn the ignition or after 30 seconds or so?

My limited understanding is that - there is likely a +ve feed coming separately to the red door lights, and there is a further current leakage to cause the three bulbs to glow slightly. May be a shorted terminal/wire or a mis-wired terminal issue..

Do try not to blow things up mate this time, k?

another suggestion: rig up a 12V bulb and two wires - ground one and check to see what your terminals on the plug in the headliner light are doing - may be a switched over wire or summat - had mine out just last week and seem to remember that one or two of the terminals were absent from the socket plug thingie....

Well, I am using my original fabia TDI door wiring looms - I just connected the interior loom to them, and they seemed to work - excluding this odd light thing.

Head tells me, if X and Y need swapping, I just need to swap around two wires, so when it's being told to light up, it won't be, and vice versa.... Maybe I'll blow another 10a fuse like I did today!