My wife has a 2012 Volkswagen Golf TDI 1.6. She specifically asked the Volkswagen garage not to apply the EA189 emissions fix when the car had its service and MoT. However, it appears that they have applied the modification as there is a yellow sticker under the bonnet and on one page of the invoice it said that they had applied it. When she queried this with the service agent he told her it hadn't been done and he removed this page from the invoice. If it has been done what are our rights?