@ speed it isn't the economics every military air craft from new in the British military has a maximum number of air hours. With the sea kings that is almost up. On most operations now winches are not used to recover causalitys as a helicopter hovering while winching is very vunerable to small arms, I would imagine the MOD no longer see that capability as a priority.
Unfortunately the Sea Kings are coming to the end of their life span. So will have to be retired from service. All the lift capabilities that the military have or will have aren't able to do this job. If the Army had brought black hawks rather paying through the nose for the new wild cat (lynx 2) then maybe it could have filled the void left by the sea king. Also with the military shrinking and pressure to save money at all costs the SAR budget is too tempting not to raid.
I have used both ready made and powder (mix you own) dehydration/sports drinks. The only advantage I have found with them is they off set water fatigue. I have been in climates where drinking up to 15 litres a day if carrying out hard exercise is the norm, after a while of that water does become a chore.