//This is nothing to do with the legality of the scooter per se.//
You're quite right. That is not the family's point at all. But it should be. The scooter their son was riding was not "street legal". The only ones that are are those in government approved hire schemes. What the family are saying effectively is "if you are going to ride an e-scooter illegally, without insurance and all the rest that goes with making it street legal, then make sure you wear a crash helmet."
Quite frankly, I've far more concern for the safety of people who stand the chance of being injured or killed by these ridiculous things than I have for anybody riding one. Pedestrians should not have to be wary of motor vehicles being ridden on the pavement and if this boy had not done so he would be around today.
This story is misleading because the tragedy happened in Bromley and the accompanying picture shows approved hire scooters. There is no hire scheme in Bromley nor anywhere near it and the scooter which caused the death must have been illegal:
https://www.standard.co.uk/news/uk/police-appeal-escooter-crash-bromley-b946378.html
I believe at least five people (including a three year old child) have died in scooter accidents this year. If Mr Pinnock's family want to raise the profile of the problem which saw their son's life taken they would be better off campaigning for rigorous policing of the illegal machines being ridden and to lobby the government to abandon its ridiculous experiment with them,.