Seriously if you've been on those driver awareness courses then you know full well that survivability dramatically increases with impact speed below 35mph.
I tried that argument with my dad in Italy. And then I looked up the statisctic about surviveablity and speed and, for, once, I think he was right: 30 or 40 mph makes little difference.
It seems it might be that only UK government-approved statistics show a huge difference below 30mph. This website, for instance, Is 30 km/h a ‘safe’ speed? Injury severity of pedestrians struck by a vehicle and the relation to travel speed and age - https://www.sciencedirect.com/science/article/pii/S0386111214000235 might suggest that we should all be travelling at 25mph.
Perhaps my lack of exposure to UK speed awareness adverts is showing. I probably need to come home and be cured