Thanks all for your views. I had a tyre blow out on my X3 a few months after we bought it whilst going pretty fast on the motorway but that was with tyres that were clearly dodgy (had to top up the pressure every couple of weeks). It turned out to be because the previous owner had bought second hand tyres which although being a good make and having loads of tread on, were about ten years old. The garage that I went to (I was on my way to the garage to get the car serviced when it went pop) said that the rubber was old and showing all kinds of weaknesses. Obviously I'd be buying new tyres for our car.

I'll have to think about it for the winter tyres. I'd likely keep the winter tyres for quite a few years since temperatures here that warrant such tyres only last for a couple of months anyway and we don't do many miles. Chances are the only car we'd replace the X5 with would be another X5 anyway so they'd likely last me a long time if stored right.

We've got RAC recovery throughout Europe with our bank but it does look like the rear 20" wheels aren't a standard size so getting replacements in the middle of nowhere might be quite tricky.