Thanks for the reply! Yes there was a problem with my MUI installation, re-installed and can now launch the preferences. All the above files you mention are in the correct places.
In AHI prefs I have 'Music Unit' and 'Unit 0' to 'Unit 3' set to 'Paula:Fast 8 Bit mono' and frequency set to '8000Hz' which I believe are the default settings. Anything I need to change?
Also, then how do I plug it in to Scumm? Can't find it in the readme anywhere, sorry if I've missed it.