Regretably, human recollection is an imperfect thing. I would, however, suggest that, in this case, the evidence of the 9 witnesses on the Mull is compelling.
Compelling indeed.
They were all in cloud. Or at least 'hill fog', in visibility which if memory serves, more than one of them describe as 'coming and going. In other words patchy.
(Incidentally, I don't recall any of them being anywhere near sea level.)
That tells us nothing of the visibility experienced by the crew as the helicopter approached the Mull in the crucial moments.
The
only '
eyewitness' to that is the yachtsman 'Holbrook'.
I well remember sitting in the FAI at Paisley as he stated: "If you are seeking to establish whether I believe the crew of the helicopter could see the lighthouse as they approached the Mull, the answer is; yes I believe they could."
Inconvenient for the likes of JP and cazatou (K52) I know, but there you are, Holbrook was there, they were not.