Topic

Any guides /help on replacing manually operated mirrors with electric ones.... wiring etc thanks in anticipation

Download the electrical diagrams, should help enormously. I have to admit that the MG-R electrical schematics are the best I have ever seen, very well draw and easy to understand. Fortunately the wiring seems to be self contained and does not utilize the BCU so its doable.
You may find that the mirrors have their own separate wiring loom...maybe worth calling some of the breakers to see whats available.
Link to the schematics is here....
https://www.the-t-bar.com/community/downloads/category/5-electrical-diagrams

Sundance

I did this many many years ago.

I don't remember much of the detail apart from making my own mini loom and that I took the power feed from the heated mirror heating supply.

Also I managed to swap the mirrors around so I now have a O/S mirror that is too low, I will change them one day but so far 3650 days have passed.....