I've recently changed my two front tyres after a year and half from new! Don't do much mileage but not bad, rears still OK. I'm not one for mix matching tyres and I like to keep things the same and original. The Pirelli's are actually a good tyre if you look in comparison to others.
Surprisingly Kwik Fit were the cheapest paid £80 a tyre and included VAT, fitting, balancing and disposal of old tyres. If you order two or more mobile fitting is free!
Thumbs up for Pirelli and Kwik Fit!