Anon, I accelerated to 40mph (the posted speed limit) very quickly to put distance between me and cars. When I saw a car inches from my rear wheel I accelerated to get away but it didn't work. Notice afterwards that the car flies into the distance? That's because he was intentionally speeding.
The bus lane you mention can also be used by taxis and motorcycles. There's a blue sign that says just that. I use it all the time, including past police cars with no issue and no fine.
nearly rear ended my friends bike at atleast 30 mph on a 20 mph road, and then carried on beeping his horn about 3 times