Are you keeping them well watered ?

have you checked for green fly?

This one keeps cropping up. It's a normal symptom of early growth with tomatoes when they have too much feed before they set fruit. As they grow on they will go back to normal.

they also curl when they get too cold and as the temp dropped recently that could be the cause. It wont affect fruiting so dont worry.

Thanks to all I think Bertiefox solved my problem