It's exactly like that, I'm telling him his roof isn't meeting building regs and all the plastic bits need putting on and he simply replies 'go and find one of my roofs that leaks, you won't, I'm right and building regs are wrong'.
I've also just measured all the batten spacings and the tiles have a headlap range of 210-255mm. His are 250mm in places and 280mm in others, at 280mm you can see the top part of the tile You're not supposed to. I've been on in all morning myself ripping the battens off and redoing them, I've worked out the gauge and put chalk lines across. It's taken me 5 hrs so far and will probably take the rest of the day.