Hi, you need to have a UK valid driving licence or a Passport in order to remove the adult content lock from your account.
Please also restart your phone for the adult content lock to be removed effectively.
You can not do it with out them.
There, there is actually an Idea in the works about removing adult restrictions using Credit Card details, so watch this space.
I would ask an agent as they may be able to do it that way, to talk with an agent sign in to the main web site and then use the support link which is mid-right and then navigate to the agent section