With regard to your answer to the correspondent AH, Sheffield who was planning to drive to Germany, I don't know if you're aware of the fact that a great number of urban areas there have been designated environmental zones (Umweltzone). To drive in these areas, which include all major cities, you are required to have a sticker (Umweltplakkette) displayed in your windscreen. Failure to do so could result in a fine. Stickers are available at the nearest TUV station to the border and cost about 10 Euro. They may be also available from a motoring organisation (AA or RAC) prior to travel but will probably cost slightly more. Any modern car should qualify for a number 4 green sticker that allows travel anywhere.