Just as an update:- I was working on another 13 plate Auris with the suspension creak. It was worse than the first one and was particularly prone to creaking whilst braking over bumps, even light braking caused it. No work had been carried out to cure this beforehand. The car had done 54,000 miles.
I sprayed silicone oil over the suspension bushes located at the front of the suspension lower arms, one on each side of the car. This improved the situation but definitely did not stop it completely. A week or so later, I applied more spray to the front bushes, but the noise persisted.
A week or more later I sprayed the silicone oil over the rearmost bushes on the front lower arms (these ones are a much more accessible rubber disc, lying horizontally). This has stopped the noise, I have not heard it at all in the last two weeks.
I have not applied any oils or greases to the anti-roll bar rubbers or the rubber strut top-mounts.
HTH.