I think what made this particularly vulnerable to making the major error the commander (particularly) did, was that the flight was actually ok - if marginal - for 24 of the 25 miles of the route, over the lower ground that formed all but pretty much the final approach. It was the rapidly rising ground of the sharp 500ft hill, towards the top of which was the LS, that suckered the commander into having a go. Had the LS been on much lower ground just 1.5 nm to the east he would have landed routinely, but trying to get that last mile or so took him in to higher ground surrounded by mist – in the twilight. He didn’t actually descend to end up 28ft above the ground – the ground rose up as he was flying along, fairly level, albeit in far too poor vis for that last mile.
If an alternative LS had been identified and arranged for poor weather use somewhere on this much lower open ground 1.5nm away, it would have been a far more appealing divert option than heading back to Wellesbourne, let alone back Birmingham which had the only instrument approach. And the flight could have been undertaken legally and safely. Given the scale of the operation I would have thought this would not have been too difficult. Maybe for other frequently used LSs on hills with low ground nearby, this would be a wise idea……
I’m certainly not suggesting the crew were not at major fault – just putting some context into how they might have got themselves into the situation.