Islander 2: Many thanks for your reply. At the end of the day, since I cannot carry a liferaft I have to assume that the CAA did not mean to restrict private flights over water in certain types of aeroplane without specifically saying so. So I'll continue to make do with the lifejacket, parachute and EPIRB... Plus I will go with the actual letter of the law rather than the aids to interpretation (which as you say do refer to liferafts):
The Air Navigation (Amendment) Order 2007 - 2007/274 - states:
(5) After article 52 add —
" Non-public transport aircraft - survival equipment
52A —(1) This article shall apply to any aircraft registered in the United Kingdom which is not a public transport aircraft.
(2) The commander of an aircraft to which this article applies shall reasonably satisfy himself before take-off that the aircraft carries such additional equipment as the commander reasonably considers necessary for the purpose of facilitating the survival of the persons carried in the aircraft.
(3) In satisfying himself as required by paragraph (2) the commander shall have regard to the circumstances of the intended flight, including in particular the likelihood of ditching and the availability of search and rescue facilities.".