Close John, but no cigar. The 826 bit's correct, but its actually just after the end of Eagle's last commission and before Tiger's first (April 1971), and occurred in Falmouth Bay. It was the very first (Westland) Sea King to ditch/crash, and the supplementary question is why????
PS I reckon the last time I saw you John was on the RN Foreign Training Unit around the time of the Pakistanis and Egyptians. Scary stuff eh? Wasn't it you who submitted the MOD form whatever (Suggestion for aircraft modification from a front line unit) requesting a larger diameter funnel on the Sea King Pee Tube as the original wasn't large enough to accomodate your JT? Sorry about this everybody (especially the ones with no sense of humour - probably Crabs), but this is genuine Old Sea King Pilot material.