I have just had a screw in the front tyre of my 2007
MCS. The runflat was still inflated, but I went to the MINI dealer for advise on repairing it. They said they could repair it, but not until the day after. So I tried to find a tyre repair place that would repair it straight away, but no one would repair it because they won't touch runflats. You might have more luck in the UK. I ended up taking back to the dealer. The dealer said they will not repair certain manufaturers of runflats, but luckily mine was a Dunlop Sport, and they said they could repair it so long as the damage was not in the side wall. They charged me $44 and even cleaned all 4 wheels and hoovered the inside
Saved me few bucks. New ones are $450+, and it's only done 10K kilometers.