Mayday Frequency
This is a 'what if' question.
Lets assume that you are crossing the channel, its a nice day and you are just enjoying the flight. You are tuned to London Info or someone similar and you can hear that there are maybe 3-4 other aircraft making the crossing somewhere near you.
Suddenly, the donkey up front decides that foreign fuel is not to its taste and stops.
Ignoring all the other vital actions, do you
(a) make a immediate Mayday call on London Info, knowing that there are other aircraft in the vicinity who hopefully would start searching for you, or
(b) change frequency to London D&D, make the call and rely on them being able to triangualate your position, alert the coastguards, helicopters, RNLI, cross-channel ferries etc etc, but lose the advantages of the nearby aircraft?
Does London Info have a big red panic button they can push to get London D&D involved?