2014 SD4 HSE When the control switch is put in the central position the light is coming on whether the door is open or not and will not go off. Other two positions on the switch work fine, i.e. OFF and the light is off, On and the light is on. Can anyone offer any help on what may be causing the problem ? ( I have done a "search" but can't find anything that relates).

A failed ( or failing ) door lock somewhere perhaps.

Each Door and Tailgate equally control the Interior Lamps via a relay that is controlled by the Central Electronics Module. This receives AJAR signals from the various Door Modules or Tailgate Release.

Page 3072 of Wiring Diagram has details.

Repair Manual and Wiring Diagrams here (named as Service Manual)
https://www.freel2.com/forum/topic10621.html

I suspect Door Module/Tailgate Latch failure (or possibly wiring loom damage?) FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 82k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)