A great example of the law not keeping up with the times. You don't have bulbs, you have diodes. They need to be replaced as a unit sometimes requiring hours of garage time. Some modern cars do use Xenon H.I.D units for headlights and these are indeed bulbs. They also pull about 18000 volts so it would be totally unreasonable to expect the Average Joe to have these available to swop at the roadside. If you really want to be covered just buy some penny diodes from eBay and produce them in the extremely unlikely event you are challenged by Monsiuer Gendarme. Wearing a beret, stripey top and necklace of onions with help you merge in with the locals and not get targeted as a rabid Brexiteer.