Ok thanks guys, seems in line with TB's experiences too. 
How does that compare to the SC3s 
Well. This is going to be pointless posting but Micheldevers records show 15k for the previous set on my current car, but I'm sure they did 5k odd on my previous car too. Hard to believe given their grip level tbh.
But, the current pair of fronts have done 9k so far, and that IS an accurate record of my own. And they are still 3mm away from the wear indicators. Shoulders don't look too bad but they will go before the middle does on the front. So 15k looks possible, maybe more.

Main reason for change is noise. Sc3 mo 235 40 18 show 73db on the eu label. More than any Dunlop, which I can believe going by TB's car on Dunlops , and f1 show 70db iirc. Plus I'm sort of betting f1 have slightly more grip going by TB's descriptions, which might match the 265 sc3 mo rears grip level better.
The price will be wear. F1 won't last as long as sc3 mo. (Although F1 will destroy sc3 Ao1 on wear, poxy things)