I will increase the pressure to 40psi this evening and see how the tyres perform. As the rears aren't Vreds should I also increase them to 40psi too?
According to the garage the geo's all within spec so he's adamant it's the tyres. I've had the suspension inspected and it's all spot on with no faults so it can't be that. Feel pretty confused tbh.
The rear tyres are autogrip

(were already on the car) 18" Monza alloys too.
Thanks for the help