Is there much I need for an assisted trek? Might get some decent shades, maybe a different, better camera, decent watch, map and compass. I dunno. Oh, trekking poles - definitely those.
Get spare batteries for everything.
Update 11/05/13:
Got some sweet, sweet shades: Bloc Scorpion (P301) Cat 3 Polarised £45 (available at Amazon for £30 … dammit). They have a nice little bridge for the nose so they fit my relatively flat face without pressing against my eyeballs. They also have some side shielding to keep the dust and wind out.
Update 19/05/13:
Trekking poles!
(with my X-Box controller for size comparison)
They’re a little too short (maybe like, 10cm) - my arms aren’t quite 90° when I’m holding them, but I’m sure I won’t notice when I’m walking. They’re super-lightweight and fold up pretty small.
Afterthoughts:
These trekking poles were a pain in the arse - I kept getting the point caught on rocks and the separate segments would yank apart. Let this be a lesson to learn to use your equipment before you go (I didn’t lock the poles properly on extension).
I didn’t take much in the end: no orienteering equipment. Maybe take a dictaphone next time - I clearly can’t be arsed to keep proper notes no matter my best intentions.
The basic (re:cheap) Casio digital watch I borrowed off my flatmate did the trick nicely, and I didn’t take enough spare batteries - I was one short for my headtorch!