You didn't say the age of your cooper, the reason are ask is that a lot of modern car use runflats as they have no spare tyre to save on space. Also some owners do the same to make room for stereo amps and woofer boxes. I know it sounds daft, but I know of at least two people who thought they would save a bit of cash until they had a puncture..when it cost them lots for towing off the M1.
If you can try COSTCO, if you have one local! They only do Michelin PILOT2, but fit, balance, new valves, and rotate all for about �55.00 a boot. Great tyres<good wear rate and excellent grip. Standard replacements on most Police vehicles.