Have the same problem and almost certain it is not a mechanical issue or tyres. With door closed look at the front edge of the door the rubber seal should be touching door and wing from the inside of the gap. On mine its is not, in two places the rubber is a few mm back. Think that the airflow across the gap(s) is causing the rubber to vibrate creating the noise. It also seems to be more obvious on windy days. Perhaps new seals or door adjustment should cure the issue. Maybe a dab of superglue to get the seals in the right position.

 

Driven the car on two consecutive days on the same stretch of motorway at the same speed 70ish! One day the noise was there the next not. So it can't be tyres (same road surface) and it can't be mechanical as the noise would have been there on both occasions. Going to have new seals fitted and door adjusted. Keeping my fingers crossed!

right the last update on this :

i have replaced o/s/f seal and my humming problem gone , very happy now ! highly recommended  

oh yeah i paid just £26 for a seal