Quick update on this, I had the car jacked up for an oil change at the weekend so I decided to spray the offending area with some oil. The main area I sprayed was the outer ARB bushes and the inner lower arm bushes.
I also noticed that the offending lower arm looks new, so I'm maybe ruling that out. Anyway it pretty much stopped the creaking noise! It's slowly coming back so I assume it must be ARB bushes if the lower arm is fairly new.