While we were in Sydney, the valet at the hotel parking garage managed to break the lock on the adjustable steering column on our Commodore, which made it a serious pain in the arse at times driving back from Sydney. Bits of an H-shaped piece of metal that was broken in two were under the dash, and the lever simply drooped and didn't do anything.
Today I decided to look into it, despite the fact I didn't actually know what the broken piece is called. I did a quick Google search for some rough keywords, and found a single thread where someone has the same problem, but no satisfactory resolution. One response was simply put bolts through the column guide, to make it a fixed steering column - we're going to want to sell this car in the future, so that's unacceptable. It was suggested that most wreckers wouldn't split up parts of a working steering column, so I went to Holden's parts department.
The part in question is part of an entire kit, Holden Part #92140565 COLUMN KIT,STEERING TILT (RELEASE LEVER SERVICE KIT) - but no Holden dealer anywhere has said kit anymore, and I can't order one. I decided to check out the wreckers in town, and yep they had heaps of steering columns in various states of repair. They would indeed sell me just the part, and I walked away with it for $5AUD.
Replacing it was extremely easy: pull the telescoping column all the way towards the driver, and pop the fuse cover off the bottom of the dash. On the left hand side of the column, just below the plastic column cover is a nut with a rubber thread cover over the bolt. Undo the nut, take off a plastic washer contraption, a brass washer, and the remains of the old spring. Slide the new part on, then the brass washer, then the plastic washer (with the metal side out), then the nut. Keep doing the nut up tighter until the lock behaves as one would expect, it doesn't appear to have a specific place it needs to be. Put the rubber cover back over the thread and put everything back the way it should be.