TD - apologies - you are of course right, and I was wrong - the RAF connection is that at least one of the pilots was killed in the SAS Hermes-Intrepid crash, and he was RAF, whereas in the earlier SK4 crash the pilot escaped, but PO Casey did not. I've edited my post above.
The RAF pilot killed in that accident near Intrepid was Flt Lt G W Hawkins, and he was with the SF guys doing FAC duties.