Cazatou,
All the observers on the Mull can simlpy confirm that the aircraft crashed into the ground at at the time was either in, or in the VICINITY (good word that) of a cloudbank. They never saw it crash. We know the aircraft hit the ground there was a big hole to prove it. Just where does it advance the cause of Negligence? How and why did the aircraft get there?
Wratten claims that negligence had taken place by Waypoint Change. If we can disprove that then his case is blown out of the water.
You have twisted and turned in the past but the basic facts are.
1. Holbrook could see the lighthouse area and the aircraft.
2. His average reported vis was one to two nms.
3. When he saw it the aircraft was clear of cloud and in sight of the sea.
4. They were VMC
We can never say for sure, as you say, we wern't there. However it is not unreasonable to assume that the aircraft would also pick out the lighthouse area.
"Flying to fast for the conditions"
Both Holbrook and the RACAL analysis have them flying slower than the average D/T speed for the whole route.
So justify negligence at Waypoint change? Everything afterwards is speculation
Negligence / Aircrew Error / FADEC / UFCM. Do take your pick. There is insufficient evidence for any these possibilities,