Ref the Gazelle accident, the real issue here is why did the pilot keep (pretty accurately) to a presumably straight line route that he had planned, rather than simply divert a few miles west, which would have enabled him to keep to much lower ground to the west of Gloucester where the cloud base was quite adequate at 1000ft. He was obviously aware of the lowering cloud base and rising ground, causing him to descend to an unsafe and probably illegal height.
He was clearly being too rigid in his navigation. Mention is made of him having a hand written note of his route, so he had flight planned to an extent. But was it because he was being too inflexible? Are pilots taught enough in training to be prepared to improvise in flight and modify their routing when weather requires?