Submerged forests or general submerged sites?
With the recent interest in Doggerland and underwater surveys of the North Sea, Solent and elsewhere, it is expected that British submarine archaeology is the "next big thing". Drowned forests are wonderfully romantic and need plotting. There are probably more than we assume. Then there are those fugitive Mesolithic footprints that can be seen for a short while off the Formby shore and elsewhere. Very many drowned hut circles and tombs lie within the central flooded zone of the Isles of Scilly too - Lyonesse.

On the negative side - be prepared for silly stuff on Atlantis and Lemuria.