What are our thoughts on these, the specifications seem well suited to caving and especially underground photography and videoing?
I have been pondering on this.I personally don't think that IP66 is waterproof enough for caving; they only start being tested with full immersion in water at IPX7. I don't like ports on the outside of lights (USB/charging) because I don't trust that they'll stay closed and watertight during a caving trip. I suspect these ports are why it doesn't pass IPX7 standards.
On a different point, the light steps out of turbo after 10 minutes to prevent overheating. More modern light designs detect overheating rather than relying on a timed stepdown.
It also weighs nearly half a kilo!
Ah - but you do much of your caving in the Dales. We're lucky round here as we have so many nice clean caves!