Seeking information about Early explorations of Chamberlain Creek

We were contacted by Dan Clearwater, author of the Canyoning in NZ guidebook and staff member at FMC about some history of the early explorations of Chamberlain Creek. If you are able to help him out, please send him a message at dan.clearwater@fmc.org.nz.
“Chamberlain Creek seems to be on the tip of everyone’s tongue when talking about Tararua’s tough gorge trips. Its featured in Mervyn Rodgers “Tararua Footprints” and Kennetts “Tararua Adventure Guide” but with very little information on the early history of explorations there.  I’d really love to hear from anyone who has information about the early explorations of Chamberlain, as well as the first trips that intentionally following the water, using ropes for the waterfalls.  I think that this could very well be the first instance of a intentional canyoning trip in New Zealand, so I’d love to know for sure!
I’d love to turn any information in to a mini-article, perhaps for the FMC’s Wilderlife.nz blog, and/or for the NZ Canyoning Association web page.  It’s a curious bit of Tararua and Canyoning history that is firmly entrenched in lore, but seemingly without much written record.”