Free Mot when you purchase 2 new tyres online just enter your invoice number into the link. Qualifying transactions will receive an e-mail with a FREE MOT voucher code that can be redeemed at national.co.uk/mot. The FREE MOT Voucher can only be used online and not in branch and can be used for any vehicle.Vouchers will be e-mailed within 3 working days. The voucher code can only be redeemed once and will be valid for 13 months from the end date of the promotion. The promotion ends on 31st October 2017 but FREE MOT vouchers will be valid until 30th November 2018.