Caravelle Interior Lighting

[cosmicsheep]

I'm trying to update the lighting in my tintop, or rather i'm trying to undo the bodge that the last owner made of it!
The door switches no longer function (despite me cleaning and testing them) and the rear lights seem to be connected to an extra foglight switch under the dash.
There's an awful lot of wires hidden in the ventilation ducting that i can't make head nor tail of and my haynes manual seems fairly ambiguous too!

So my question is this, should the rear interior lights have been connected to a door switch? either front doors or rear sliding doors (of which i have 2!)
And also, what is access like if i remove the headlining?

thanks

[Mickyfin]

For reference, my interior light above my drivers door, and the rear interior light on the same side are both operated by the drivers door pin switch, and the sliding door pin switch. No pin switch in passenger door.