I have just had a new roof installed, I have noticed that some of the tiles are cracked, what should I do?

If some tiles are cracked then these should be replaced straight away. The most probable cause is foot traffic; ie the roofer has walked on the tiles. If the underlay has been installed correctly then the roof shouldn’t leak in the short term, but water leaking onto the tile battens and underlay will cause these to rot in the longer term so it is wise to replace any cracked tiles sooner rather than later.