Well you're right @masda74 I didn't end up looking back here for quite a while as I solved the issue not long after posting!
In any case it turned out to be a multitude of issues including a faulty board in the ICC (explains other issues I had with the air con control), a dodgy replacement fuse that I later replaced again with a good one, and damaged wiring going to the ICC (I pulled it out to have a look and someone had previously had an aftermarket stereo hooked up and butchered cables back there. Didn't look like they knew what they were doing at all so once I fixed that up it was all sweet).
I usually operate on Facebook in various groups unless I can't find answers there, and haven't got into serious modification yet as am still locked down by pesky green P plates here in Victoria. Looking around though I thought you guys might appreciate a thread revival more than a repeat question haha so thankyou for the help in any case!
I'm thinking of becoming a donating member at some point though...
Dulkie