Tiny - manually inflated jackets are what you need - an automatic one may inflate whilst you are still in the aircraft preventing you from escaping the sinking fuselage.
Protection - first rule of survival - an immersion suit will save your life - the water temp is 11 degrees C at the moment and that is chuffing cold.
Location - second rule - a PLB/EPIRB
Water - 3rd rule you'll be in a lot of it but not for long so you shouldn't get too thirsty.
Food - 4th rule, eat before you fly - more energy to survive the cold.
Ring us at the SAR flight at Chivenor if you like to let us know when you are going since it will be either us or Waterford that comes to get you if you take an early bath.