LPG bottle (in use) stored outside gazebo

by Joy
(Liverpool)

I have managed to get the LPG safe certificate. I called at least 23 engineers listed in gas safety site only one of them agreed to pay me visit and check my pop up kitchen that uses 2 gas bottles. My question is. Is it really non-negotiable to keep the bottles thats in use outside the gazebo? I understand for the concrete structure. It says in policy it has to be outside structure but I m not sure how is it any safer not keeping it within structure. As the structure is actually gazebo and not prominent wall.
Please help