Does the tree have any buds under those leaves or on the branches? I have seen a lot of Bay trees affected by the winter weather - mostly they have been in sheltered but northern aspect spots. Bay trees need full sun.

If they are standards, with a bush at the top of a long bare stem you may be able to cut the whole thing down to about a foot high and it may break again from the base. i have done this successfully - but best grow them on as round bushes rather than try again for standards.

thankyou for your comments I will keep you posted as to their survival hopefully