Hi NutLoose,
Yes, the old idea was the helo was downed at sea. In fact, the ARG Army idea was the helo was near Sea Lion Island (and they have a painting with that info!)
But new evidence (Coventry BoI, REME map, post war reports of wrecks, Ghurka´s survey of Lively, Ewen ST testimony, and many others) suggests the helo crashed over land or, at least, near the coast. As hard evidence, a Puma propeller was found in that position a couple of years after the war.
Best,
Mariano