As I have said for many years, understanding the local weather generated by the headland is germane to understanding why they could see it but judging distance to it would have been difficult.
By all accounts, it was typical with a southerly blowing - on the day, the orographic cloud started at about 800ft obscuring the higher topographic features;
the lower slopes, with the strong wind blowing off the sea and so late in the day, a thin layer of mist ran up the slopes close to the ground blurring ground textures on that already featureless slope (bugger all trees, etc) - imagine wet DPM steaming in front of a fire) - you could see it (as the yachtsman said) but it would be difficult to judge the range;
you could stay clear of it visually but if you wanted to approach (for whatever reason) a particular spot on the land, it would be very difficult to judge your closing range - and if something you should have been able to trust was giving you the wrong range, you would have a hard time detecting this,
The navigational analysis showed a deliberate turn to the right close in (see earlier posts) and the control positions and responses combined with the engine data indicated an awareness of their proximity to the ground at the last moment and that they had control - while they had knowingly approached the ground they were evidently surprised at just how close they had got.
Gentlemen, you have had 16 summers to go up there and see for yourself just what local weather is generated by a strong wind onto the Mull (it's common enough) - we are getting close to the anniversary of the crash - get yourselves together and hire a boat; stand 1/2 a mile or so off the coast at tea time when a moderate or strong southerly is forecast.
You could make an outing out of it - pass the time with a game judging how far off you were (get the skipper to move about a bit and check your answers with his radar) or chatting about whether the Mk2 was built like a Lada or a Rolls - and whether it would have made any difference to the crew heading towards the land at 150 kts if they had been being misled by some device as to their actual range to go.