In a perfect world, a tire sealant kit may sound like a quick, convenient way to fix a flat tire. No need to remove the tire—just add sealant, inflate, and go. But, it turns out, there is more to it.

Seems nobody can change a wheel any more. Try Slime Quick Spair for £9.99. Fix it on the tyre valve, press a button and, ta-da, the puncture is mended. The sealant can be removed and the tyre repaired ...