I recently had my car serviced, I purchase beforehand the BG244K Essential Fuel Additive, according to the service schedule this was not added (indicated by a 'x') So I rang the centre and they checked their stock levels and they said that it was added before the service took place and it was just a mistake on the service schedule paperwork It was only £19.99 but for peace of mind is there any way I can check this was actually added?