This intermittent noise is driving me crazy! Can be described as a faint electrical buzz noise that comes from the top door side of the driver seat. I can hear it over my right shoulder side. I presume it's the airbag?
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.