Under the most recent Intoxicating Liquor Act a decision whether or not to allow children in a pub is at the discretion of the licence holder. Once a licensed premises is 100% one way or the other there are no discrimination/equality issues and it is perfectly legal to have a sign saying 'Children not allowed at any time'. Similar to having an Over 21's or Over 23's policy, if it is not enforced unilaterally but rather is used by management selectively then they leave themselves wide open to having discrimination cases taken against them.