Fuchsias, even hardy ones, are susceptible to frost through the roots if they're in pots. If you have any soil or border available, bury the pots up to the brim - the fuchsias will die back down to the base, but when winter is over, lift them out as growth begins and cut back as necessary. If you don't have a piece of ground to do this, wrap the pots in a couple of layers of bubblewrap or horticultural fleece, or both, stand them closely together against the house wall or in a sheltered, sunny spot.

Or wrap them and keep in garage or GH, they don't need light during the winter months, keep slightly damp, I lost some by keeping them too dry.

Thankyou Lizziebee and Bamboo.