Having used mix of Morrison's, Asda & Tesco fuel for as long as it has been about in various cars including Lexus GS300 for 6 years (60k + miles) GS430 for 7 years ( only 26k miles), Rover827Si, Audi 100, Hyundai i30 to mention but a few I can see no reason not to use their fuel. To date none of my cars or wife's cars have had any fuel related issues and have given excellent fuel consumption. I do, however, respect that some people do not trust "supermarket fuel" and don't use it - which is their prerogative.