Bear in mind that the bayonet connector is tiny (4-5mm).
Got it sorted mate,
The red connector I've fitted to the cable; slides on to the spades of the existing unit no problem so I assume the extra connector on the ambient unit is the same size,
Cable is now in place and spliced to the bottom left cable on the rear of the light switch unit coloured
I've tested it out and yes it becomes live when the driving lights are turned on.
I've taken the front light unit out now and swapped it with the single bulb unit in the back seat,
So now back seat passengers have a reading light on either side aswell as a courtesy light in the centre.
Was a straight swap all cables are there.