The Natural Philosopher wrote:

Driver always responsible except for adult rear seat passengers

Depends how you read the columns, what makes you think the 4th column
only applies to the corresponding row in the 3rd column, rather than the
age/height of the person from the 1st column?

Granted the various statutory instruments, acts and amendments are
difficult to get straight on line, but is this clear and definitive
enough for you and Sam?

http://www.direct.gov.uk/en/TravelAn...ice/DG_4022064

"Anyone travelling in the vehicle aged 14 years and above is responsible
for wearing their seat belt"