Distance: 8.8 km (10.0 DOC hours) - Unmarked route, clear - Easy-moderate terrain
Altitude: 397m to 2081m. Gain: 1923m. Loss: 266m . Gradient: 15 deg (Steep)
Skills: Snow / ice (5/7)

Unmarked route, clear (7/9)
Unmarked route, follows obvious geography (river, spur, trail, etc)

Secondary, unmapped (4/5)
Route not on maps, an alternative recognised access to hut or along range / catchment

Steep (difficulty: 5/5)
Steep climbs of >1000m

Easy-moderate (difficulty: 2/5)
Tussock / river-gravel / open bush / cut track

Snow / ice (difficulty: 5/7)
Scramble with snow/ice sections, ice axe & crampons required

Unknown (difficulty: 0/6)
Not specified

Unknown (difficulty: 0/7)
Not specified

No description

Note: Described in the reverse direction to your journey

Canterbury/Westland guide has a good description of this route. The descent to the Bettison Lake is straight forward until a final rocky buttress. Careful route finding was needed with some down-climbing. After the first 20-30m, the descent was by zig-zagging on good rocky ledges.
Bettison Stream is followed on TR before making an ascending traverse above the scrub. There is a large cairn on the ridgeline at the edge of the boulder field. Traverse the boulder field, there were not many cairns in 2015 until the latter parts of the traverse; don't be tempted to descend. The marker poles for the start of the track only came into sight about 50m above them. The track is steep but well marked.