Thank you for responding to my query-the only one to do so. I took my car into the garage in desperation. They had no difficulty in identifying the problem which was blocked drain holes under the scuttle panel. Unblocking them took half an hour and I was only charged £49. Apparrently this can happen in Piccasso C4 cars from time to time so if you get another query of the same type as mine, you will be able to solve it quickly. Thank you for your trouble.