Thanks for the advice everyone. So far I've been quite disciplined with taking photos before I pull something apart. I'm sure I'll get over-eager at some point though :)

I'm going to check out Jaycar for the fuse holder tomorrow. They don't have one like it on their website, but I'm hoping they may have something suitable instore.

Zedman, yeh that's why I'm looking for a replacement. It looks like a previous operator had stuffed some string into the thumb screw top to effectively make the whole thing longer (probably to compensate for the spring no longer working very well). I'll fix it up properly.