Wellies are a MUST here as it will be muddy. Cache is only accessible at low tide when you can walk out to the starboard towers. The mud can be sticky and hard to walk through so go as far as you can down the shorelne and get as close to the second tower as possible before heading out across the mud. The closest shoreline point to the tower is only about 300mtrs away and the walk across is far less muddy at this point.
The cache is a small nano screw cap "dog tag" which is not hidden from view as the journey here is hard enough.
From the car park follow the path through the woods and down to the hard path through the golf course. Follow the path and once you leave the golf course do not be tempted to follow the river sign to the right. Instead go straight ahead and follow the track and get as close to the shorelins as you can. There is a gate through a field which will take you down to the shoreline and to the closest point to the tower.
PLEASE MAKE SURE YOU CHECK THE TIDE TIMETABLE AND HAVE PLENTY OF TIME TO FIND THE CACHE SAFELY. From the shoreline to the cache and back again can be done easily within 1 hour.