Here's why I'm not sold on the hypothermia tide of opinion -
Hypothermia does not reach the stage of feeling hot (paradoxical undressing) until it is fairly advanced, the link says moderate to severe. By moderate stage the persons muscle coordination is poor, fingers and toes blue, movements slow and laboured. By severe stage the persons breathing has slowed, so too blood pressure and heart rate, inability to use hands, walking nearly impossible.
To be paradoxically undressing and burrowing, Gaia removed fiddly items (bra and trainers) with blue extremities and poor muscle coordination, and then presumably now naked in the elements, so not getting any warmer and likely to succumb to the cold very quickly, she didn't exhibit burrowing but climbed a gate and continued to walk for quite some distance across difficult terrain with bare feet, with walking nearly impossible, she still managed to make the effort to burrow into the gorse. She didn't collapse on top of it or she would have been seen by the searchers.
Add to that the undressing at RD's flat. She can't have been hypothermic in the flat. The undressing twice (if true) sounds to be unconnected with hypothermia, to my brain.
I also think there is a good chance she would have been seen, and heard, if she was crying or in a state of delirium, with it being a common time to walk dogs at around 5pm, whatever the weather. If she hid in the field for a while and got really cold and wet I don't see how she then picked up energy to move the distance she did from her clothes. I would have expected to see the burrowing near the clothes with the expected lethargy and other physical characteristics.
