Humble opinion coming up...
I reckon that this helo is in a (more or less) max rate dive.
1. The rotor blades seem to be in a forward flight configuration; i.e., the rotorblade at the pointy end of the aircraft is more bent upwards than usual, while the other blades are rotating in more or less their normal configuration. If it was in level flight, one would expect all three blades to be almost maxed out (or, at least, the blades at the rear would be bent further 'upwards'), as if it were performing a vertical take-off.
2. The crew chief/loadmaster (visible in the door), while holding on, appears to be standing more or less straight. If the aircraft was in forward flight, one would expect him to have his hips hanging down slightly.
3. Helicopters will maintain constant altitude up to incredible angles. However, I reckon that this one is too far over to maintain level flight.
Bearing in mind the aircraft's mission, it would not surprise me in the least if this was practicing the helo equivalent of the Sarajevo landing (fall out of the sky, under power, and plonk it on the ground), somewhere near Odiham.
Like I said, this is only a guess (haven't yet worked with the Shìthook) and feel free to disagree.
The definition of a 'Pessimist': an Optimist with experience...