I have seen in one of the catalogues, a white plastic, self-adhesive
corner
piece. It attaches to the top edge of the tub, and the side of the
wall/enclosure, and is specifically designed to solve the problem you
describe.

Called "dripguard"... plumbworld.co.uk have them.

No experience but will be trying one to solve a shower-over-bath problem of
my own.

mike