This is not something I have seen mentioned before but there are differences in the way the interior light functions on post 1998 cars...or thereabouts.

my earlier Scottie just ha s alight that goes on an off with the doors. It does not fade either.

The later LE has an interior light that fades but also comes on when the ignition is turned off.

Also the central locking is affected by the boot light and will not lock unless the boot is closed. This does not happen on the scottie.

I presume these features were added for the LEs and subsequent Plus and VT 6 models?

Dunno: my 16 has fading-after-delay - but with a completely different controller, and so does the 97 (I think) loom and bits I used on the kit. It's a simple change in the box under the seat - even just a software change.

But I think your scottie should fade.

The crashed Nov´98 20vt I have doesn´t fade, comes on when the key turned off and is unaffected by the boot light, simply on/off. The present Dec ´99 Plus fades. Both have the non-locking feature when door/boot open or improperly closed. The boot lid operates over one button only, for light and locking sense, so shouldn´t be issue if one of those two functions right...

Worth a glimpse into eper to see if there's a part number change on the controller, then?

Only the one listed in eper

My 1999 20vt interior light fades.

After installing a rear light a few weeks ago [with quite a bit of help I should add] it now comes on with the door opening, fade n'all, P reg.

It just disnae operate independently when wired up in this way.