I went down to the river and got some pictures (below) and spoke to the Channel 7 crew that was on the scene first.
Guys in the helicopter (two) seemed to be okay, one had some superficial head cuts and the other some cuts on his hand but otherwise looked okay. I didn't see them there personally but saw some camera footage that showed the guys getting treated and they looked pretty much okay, just a bit waterlogged.
Speculation at the moment is that he came in too fast, possibly caught something, tail rotor dug in (you can see some damage to the surface of the helipad itself), spun around and flipped over. Channel 7 crew was across the river at Southbank filming something and heard the helicopter coming in, switched off their camera to wait until the noise finished, had their backs to the helipad when they heard a bang and they turned around to see the helicopter on its back already. So the speculation that it happened "on takeoff" doesn't sound right.
Apparently some blade parts were found across the river at Southbank, fortunate really that nobody on the riverwalk was injured. Lots of fuel in the water, very heavy smell in the air.
A big thank you to Graeme at Blue Tongue for hosting pics:
Blade parts pulled out of the water and put on the walkway - note brown mark on the helipad where something (tail rotor?) dug in:
The walkway is holding up the front of the helicopter - lucky the handrail didn't go further into the cockpit area.
