Why look for rules when there is no need for them? Despite the best efforts of the bureaucrats the other side of the Channel you may, as PIC, fly any passenger as long as you take responsibility for their safety which is your duty under the ANO and our well established common law system.
I have flown my sons since they were babes in arms, which is why they all now have PPL's; our dog sat calmly through gentle aerobatics and when one of my sons won a goldfish in a plastic bag at a shooting stand at an airshow it too survived a few loops on the way home, kept swimming for several years once back on terra firma.