Thanks for the tip, hadn't heard of these. I'll bare them in mind for the future but looks like they might need replacing each time you switch over tyres(?), and as I've been taking the van skiing a lot I switch tyres twice a year between winter/summer.
Also, after my tyre exploded I'm quite sceptical how useful anything would have been. It failed quite suddenly and spectacularly, exploding at 70mph. I actually thought something in the engine had failed as I could see debris in the mirror and everything was shaking. I was so lucky it literally happened at the entrance of a lay by on the A42 and I retained complete control. Scary stuff though.