MMmm, Solicitors sometimes cant even give legal opinions so I wont give you a legal anything. In short answer there are alot of waters in England that have been used, namely freshwater ones I have 4/5 marked on GE that various people have used.
As regards landing on the Sea, its only G-ESSL I know that uses it regularly but as far my flying budget goes the salt water would just blow the whole lot on maintenance. Its rarely suitable, and wouldnt be a good plan for everyday use. I have a lovely LA-4-200 for Sale if you want something sensible to use off whatever place you choose. PM if your interested.
Irish