What sort of mileage have the tyres done, and how much tread depth is left ?

My C5 2.2 estate is a bit older (2001) and is on 205/65 tyres so sorry, not directly comparable. For what it's worth, though, mine came with Michelin Energy tyres and up until the most recent set I have always replaced with the same - they were always very good for performance and low noise. However, I've just put on Michelin Cross Climates and they are phenomenal: very reassuring roadholding and even quieter than the Energy rubber. So you could definitely try that when it's time for new tyres.