It would have been something along the lines ofWe don’t know what instructions he was given by the signaller, yet. But we should never assume as... you know the rest!
"You are authorised to proceed at caution, wrong-direction as far as the crossover, which is set and locked for you to cross over onto the opposite line. You may then proceed in the right direction at full line speed and obey all other signals."
There would be absolutely no reason for the driver to proceed at caution once he had crossed over to the opposite line. As has been said, he had already passed that way sometime earlier without incident and another train (the one who reported the first landslip) had also passed along that line. No landslip had been reported on that section. I'm surprised that there wasn't a blanket speed restriction due to the extreme weather conditions, however (e.g. we had a blanket 50mph speed restriction yesterday due to the storm. That was made more excessive in some areas along the coast and some sections on sea walls etc were then closed altogether).