The instructions for parental contrrol are really confusing. On
http://www.o2.co.uk/help/nspcc/child-protection it says "If your child has an O2 mobile, our Parental Control service only allows them to visit websites that are suitable for children aged 12 and under". Elsewhere it says only 18+ sites are stopped. I've also seen another page which says that the 12+ restriction is optional. Trouble is I've no idea how to access that option to turn it on or off.
My son's phone is currently stuck with <12 content. I somehow managed to turn that on a while ago because I didn't want him to use it for social media. However I now realise it's so restrictive he can't even access the Transport for London website to find out when his bus is due. I've been trying to figure out how to switch it to <18 instead, but have reached a very frustrating dead end after several attempts.