foxmoth said:
in fact there is no reason this group member could not go to his group and see if he can get them to endorse him allowing him to let Weeman fly it as he does - but HE would be the aircraft commander not the group member
Not so, there is one very likely reason: if the aeroplane isn't maintained to public standards (and most group owned aeroplanes aren't), the legality would then depend on whether Weeman pays for the privilege. If he pays anything towards the flight, it would constitute illegal public transport!