Thought I'd post an update in case it benefits others. I've wasted a lot of time looking at the driver seat area.
Cianpars and Algie you were both right!
I don't have a driver side sunglass holder
just a grab handle above the door. Decided to lift it slightly when the noise appeared and he buzzing went! Some small cut foam or similar under the grab handle will fix it.
2 people were convinced it was the driver seat.