YANBU
If you are being tailgaited, it is the official advice of the Government that you slow down. So even if you are already at 20 mph and you are being tailgaited, slow down more.
It is not true that just because the speed limit is 60 you are allowed to drive at that speed; it is obviously illegal to drive dangerously. If you have a clear view with no bumps, bends or or other roads or driveways joining your road ahead, then you can drive at the speed limit.
The rural road between my house and my children's school is national speed limit (although where there are houses it is 30 or 20). Police frequently turn up on the road during the school run, and stop people who are under the speed limit, but over what it could be considered safe to drive given the conditions and the presence of pedestrians/cyclists on the road.
If you are in a rural area, there usually aren't any pavements and you are sharing that road with pedestrians. Slow down. It is rarely safe to drive at 60.
I wish (and I know this is massively contentious) that we had a law like Cuba's, where if you killed a child while driving, you automatically went to prison. I can't see any other way of getting drivers to realise that in areas with no pavements, the roads are not just there for them.
Our police presence, and the involvement of our council in monitoring the road, is down to campaigning by local people. If you want people to slow down, campaign locally.