Both Shell V-Power and Tesco Momentum 99 contain ethanol, up to the max permitted percentage
Marketing and Advertising is a powerful thing
In the UK, we have a limited number of refineries/storage in the country (12, of which only 1 in Scotland - Grangemouth). All fuel, branded and supermarket, comes from the same hole in the ground or ocean, and gets refined and stored in the same refinery tanks. Southern supermarket tankers draw their fuel from the Esso Fawley refinery, this also feeds via a pipe to the Shell Hamble depot, and a pipe to the West London Terminal that feeds Heathrow.
It's all the base stock, that gets delivered to Shell, Esso, Texaco, BP, Asda, Morrisons, Tesco, Sainsbury's etc. Same with Stanlow on the Wirral, Lindsey at Grimsby etc.
The difference comes when the tankers fill up - the driver punches in a code when filling, and the correct additive package gets added to the tanker "pot" for that particular brand/type of fuel.
Stand outside any refinery for long enough (and you'll get arrested), but you'll also see all the different tankers from Shell, Asda, BP, Esso, Morrisons etc. all drawing from the same point.