What pressures are you running up front Martin?

re: tread wear rating.
You can use the TWR number to compare tread wear between tyres within a manufacturers range but it's hit & miss when you start comparing (for instance) a Bridgestone against a Michelin.

The RE050A Bridgestones I have sitting in the garage have a TWR of 140. I know they wear (slightly) better than the numbers suggest.

The Michelin Primacy HP touring tyres I have at the moment have done 58,000km & will go to 65,000km. TWR is 240. I would have expected them to last about the same as the 46,000km I got from the TWR 280 CSC2 that came with the car but Michelin appear to have added concrete into the rubber mix.