Having exchanged with Beejay (Barry), I think he prefers the 2nd manual replacement dial switch method, as per exists in the car, as he already has one spare.
I'd rather ideally a remote device, or a just a two move rocker switch, one click for sides, the second for heads, as a simple extension of the two main functions on the existing set up.
I hardly use the spots, so to avoid complication, if its the non remote route, they can be left to operate as they are normally.
I hope this helps and I'd like to thank both you and Paul for your kind efforts.
Really much appreciated ...