So, nothing in the laws to say you can't have 7 metre goalposts and 9 metre behind posts...2022 Rules On Goal Posts
3.3 GOAL POSTS AND BEHIND POSTS 3.3.1 Position
(a) Two posts, to be called goal posts, shall be a minimum height of six metres and a maximum height of 15 metres and be placed at each end of the Playing Surface at a distance of 6.4 metres apart.
(b) A further two posts, to be called behind posts, shall be a minimum height of three metres and a maximum height of 10 metres and be placed at a distance of 6.4 metres on each side of the goal posts so that a straight line can be drawn on the ground to join each post.