I was in Caswell bay, a good surfing beach just west of Swansea, South Wales. The waves come ashore as in any other beach. Similarly, beaches on the opposite side of the Bristol Channel, 23 miles away,  also receive waves coming onshore - in the opposite direction to my waves in Caswell. How are waves generated in a funnel-like Bristol channel that impinge on both opposite shores. Surely, the wind does not have enough energy or distance to generate these - does it? If so, the wind must blow in opposite directions from mid-channel - surley impossible!