Hi James,
Yes this is the same spot on my CVRT Samson that I am restoring, the gearbox bay tunnel.
So next job is to drain the water out of all of the torsion bar tunnels.
About 20 years ago I was looking after a closed down Mill, there was a very hard frost for about a week, and the factory pipework , boilers, valves, heat exchangers, etc up to 1/2 inch thick steel was completley destroyed.They demolished the factory in the end.
Regards Peter