My cousin had some good suggestions of how to spend the day. We plumped for a visit to Burgh Island, driving along the Avon estuary as there is a road exposed during low tide, which makes the journey rather interesting. We saw masses of birds, all poking about in the mud flats.Burgh Island (http://en.wikipedia.org/wiki/Burgh_Island) sits across a large expanse of sand from Bigbury, cut off twice a day by the tide travelling in and out of the Avon Estuary.
We walked over to the island, and were rather entertained by the sight of a tractor towing an ancient, small fishing boat, across the sand, complete with crew on board. Only in Devon!
The equally ancient tractor then backed carefully into the sea, launching the boat in a very sedate and well-practiced routine.