I think we've sussed it. It has 3 pilot sport 3 tyres on, and one pilot sport 4s on the front nearside.
the two rears have about 5-6mm of tread, the offside front has about 3mm, and the 4s on the nearside has about 6-7mm
swapped the two evenly worn tyres from rear to front, and seems to drive much better.
still very skittish under acceleration on a bumpy road, but that's FWD for you I guess