there is a lot of new information out that parents are taking their children out of seats too early, and that it is recommended that children stay in a high back booster seat until if possible the age of 12.
GMTV will be starting their new child car safety campaign soon, and this will be a big focus
You might find this site useful for more information and advice
http://www.childcarseats.org.uk/
If you can't find anything on there then it might be on RoSPA's main site which I can't remember off the top of my head