> but in practice it's the minimum you are expected to drive.
No, it's not. Far from it. A speed limit of 70mph on a motorway is not the minimum, just because you, or other vehicles want to exceed it.
A speed limit of 20/30mph in a city center is not a minimum; it's actively dangerous to exceed it, and if you regularly exceed these you are a danger on the road.
A limit of 60mph on a national road is often granted based on road classification rather than the actual road; There are numerous A roads in Scotland that are _not_ safe to travel at 60mph for large stretches of due to poor road camber, poor visibility, narrow lanes, etc.
> I do have a bike and I always get off the road to let cars pass when there is one nearby.
This is a dangerous and unpredictable way to cycle, and can lead to cars overtaking you when it's dangerous to do so/they're not confident to do so, in the same way that an unconfident driver travelling at 40mph on a motorway is dangerous, or a car driving in a hard shoulder to allow overtaking is dangerous.