Success!
I carried out a few more installations last night, and hit the same blue screen of “thou shalt not pass”-ness.
I then hit upon http://hpminiosx.wetpaint.com/ which is a wiki devoted entirely to hackintoshing the HP / Compaq Minis.
Reading through the instructions there, and something hit me.
Both tutorials mentioned using OSx86 Tools, but the tutorials I’d followed didn’t really touch on that.
So at the point where I had originally got to, i.e. a working OSX install, but BEFORE installing any of the kexts, I fired up OSx86 and had a tinker, and realised that you can install the kexts from here, instead of kext helper, so I thought I’d give it a go.
Step 1: Installed the non-video kexts – rebooted – no problems. Ooh, Airport detected! Ooh, battery icon!
Step 2: Installed one of the video kexts (I was convinced that these were what was causing the problem, so I held my breath) – rebooted – no problems (same low resolution though)
Step 3: Installed the OTHER video kext (yes, this must have been the killer one) – rebooted – STILL no problems (but still the same low resolution though)
Hmmm… So I’ve installed the kexts, but still don’t have the correct screen resolution. Re-looked at the WetPaint wiki instructions, and spotted something that the other tutorials never mentioned.
Now open up UInstaller.
1. Select your Hard Drive under Drives
2. Choose OSx86_Essentials as the package to install
3. Click “Apply kext package”
Wait – how did I miss this?
I followed those three steps, and rebooted, not expecting anything because I’d done things entirely out of sequence.
WOAH!
I have full resolution (1024 x 576), my audio works, my wifi works
No idea how I missed that step, but hey, I’m sorted!
Now I just hope I don’t break it 
