On a visit to D & D, some years ago, we were told the story of the guy who ditched his PA 28 south of the Isle of Wight (maybe even at night I think). He did not get through to anyone.. (too low).. but got picked up very quickly.. How?
Well, he squawked 7700 and the alarm bells went off for a very brief second at D&D, even though the squawk was only seen on ONE radar sweep, as he went into the water.
The guys replayed the tape several times, plotted the position and sent the chopper out.
A VERY relieved pilot.
Moral...get the squawk on IMMEDIATELY.
Then talk to 121.5...preferably to a Brit..so as to remove any language problems. (IMHO).
UV