These clay ridge tiles show the results of being exposed to high winds combined with poor bedding in mortar.
They are in danger of blowing off in the next gust of wind with resulting damage to the adjacent slates (passers by and the new car parked in your driveway) and probable rainwater penetration damage to the roof space and living accommodation.
They need removing and rebedding in a suitable mortar base as soon as your roofer is available..