Operating at 300 ft agl 5 miles south of Gatwick where the airliners are all up at 5-7000 ft should not be a problem.
But he wasn't. I know that area - he would have been approximately 800m laterally from aircraft on final for 26L at around 1300ft AGL. You tell me if that is legal. And what he was attempting to do (photograph the aftermath of a fire that killed 2 children and an adult) was distasteful at best. So plod have my full backing tbh.