My DS is almost 12. He has just joined Y7, likes to meet up with friends and often this means going out on bikes. He took his cycling proficiency earlier in the year. None of his friends seem to wear helmets and I have, so far, insisted he should. He doesn't want to though as this makes him different to his friends. Should I insist he wears one, advise him he should but let him decide or not let him out on his bike if he doesn't?