Turned out to be the 20A fuse in the panel at the end of the dash, a replacement fixed the issue, I wonder if there is an intermittent short.

 

I never need to move my seats as no one else drives my cars but I can see the flexible section of the harness to the two connections on the back of the Seat Module could either have cables in the bundle break over time with repeated flexing or the insulation rub through and short.





Similar to the common harness breakage at the luggage compartment hinge point on saloons and Coupes.

Graham