no, thank you for replying, it definitely is a help, your reasoning for not believing it's the relay makes perfect sense. I was trying to work it out via process of elimination so just went to the next link in the chain.
I have a relocated battery with a fuse close to the battery and another one in the fuse box so I've checked both of those.
I'm not sure what you mean by relay closest to the front of the car as both of them in the australian version are sitting side by side parrellel to the dash so it's either left or right.
I have had some luck perhaps on another forum where I was advised the switch itself is a well known point of failure and usually cleaning the contacts is all it needs to fix it. I'll try that tomorrow