This is the Pyke Creek located in the upper Haast Valley, draining the Brewster Glacier, by the popular Brewster Hut track.
First descent 2004, by Alain Rohr and friend Andrea.
Alain reported “v3a3III*, approximately 3 absiels to 25m” and “A lot of boulders before the last absiel, in a nice small gorge. Nice entrance”.
In February 2020, a team of 4 from the Wanaka Canyon Rescue Team partially descended the canyon in the search for a missing hiker. They placed some bolts during the descent, but were extracted by helicopter from part way down the canyon with the deceased hiker.
Therefore any group descending this canyon can’t expect to rely on anchors from the first descent, or the SAR operation. So the next groups through must be prepared as though it was a first descent, and take more rope and anchor equipment than suggested by the anecdotes. The canyon is fed by the Brewster Glacier; expect cold conditions and for flow rates to increase as the sun heats up the glacier through the day.
Photos below are mostly from the Wanaka SAR Facebook Page, from the search in 2020. The final image is the last obstacle from below, taken on a hike up the creek from the main valley.
Looking at the imagery, the author of this site thinks the grade is more likely to be a4.