I had a new roof in 2021. It’s come to my attention that the roofers have failed to install kingspan. According to several roofers I’ve spoken with this is in contradiction with building regulations and to rectify the situation all the tiles will have to come off. The guy that did the work says it’s not true about building regs and that the boards can be dropped through the gaps in the attic. Can anyone shed light on who to believe and what I should do.