Why are people making the presumption that statistics, ideas, concepts, etc from another country will be applicable here.
1. Human heads are the same
2. Helmets are the same
3. The laws of physics are the same
4. The Australian case etc exactly correspond with what has happened in the UK as helmets have been worn more often: ie there has been no detectible benefit from wearing one
History is littered with examples of things which, often seemingly defying all logic, which work out completely differently when transplanted to the UK. Crime levels and 24hr licencing is one - in every country in the World, including Scotland, crime levels related to alcohol dropped after its introduction, but in England they actually rose sharply.
Yes, but that's about culture and human behaviour which does vary society to society. Whereas the amount of energy that 300g of packing foam can aborb does not.
To examine statistics applicable to another country and to expect them to be applicable in the UK in general, and England in particular, has proven through history to be an extremely flawed exercise.
This is utter Daily Mail reading crap. There are certainly special cases, but all sorts of assumptions and models used in epidemology and insurance - ie almost all that matter and that are relevant - work perfectly well for the UK.
Even in the case of alcohol laws what you havew written is untrue - the UK didn't react like the Mediterranean countries, which hardly make up the whole world! Deducing that British heads will somehow gain 10,000 Joules of energy absorbtion from a helmet specced to provide only 100J, when Australians do not, because Brits have different drinking habits to French people is just insane. The accidents that kill British cyclists are just like the ones that kill Australians; +90% of them involve +100 times the energy a cycling helmet is designed for.