I, I, can't see any real difference? http://www.halfords.com/webapp/wcs/...ick&langId=-1&catalogId=10151&ddkey=ClickInfo Just that it is compulsory for 3-11 year olds to have a suitable restraint (which I thought was law anyway, but realise that it was 'optional') Neighbours seem to think that a child up to 11 needs to now sit in a fully bolstered car seat and that a child booster won't do. But the law isn't clear, and I'm confused. I did a search on the Britax site (which is probably one of the largest manufacturers of car seats) fit finder http://www.britax.co.uk/FitFinder/GB/CarSelection.php and no car seats for a larger child (group 3) are suitable for either my Mercedes E or Avensis! Also the car seat manufacturers categorise the child requirements in weight, the law has specified height :-S .