The above replies made me wonder if I was mistaken about lead shot/fishing weights being banned, so I had a quick Google.
The current regulations appear to be:
In England, Scotland and Wales, you must not use lead shot when shooting with a shotgun over a foreshore area or over listed Sites of Special Scientific Interest (SSSIs). The foreshore, also called the intertidal zone, is the area of shore that lies between the average high tide line and the average low tide line. In addition, you must not use lead shot to shoot any swans, ducks, geese, coots, moorhens, golden plover or common snipe. No restrictions apply to Northern Ireland.
Lead fishing weights weighing less than 1 ounce are not allowed.
Rick