Tesco. They have Sarsons distilled white vinegar, and 'non-brewed condiment' . All vinegar is mainly diluted acetic acid. In the case of Sarsons, this should be obtained by brewing cereal grains, followed by a distillation process. The 'non-brewed condiment' is obtained by direct distillation from anything else, from wood to North Sea oil. The 'non-brewed' used to be called vinegar, but vinegar brewers objected and the use of the term was banned. There is a taste difference between the two types, and customers in Scottish fish-and-chip shops still have a preference for the taste of their non-brewed 'chip-shop vinegar'.
But in the case of baking brownies, there shouldn't be any difference. When did you ever taste the vinegar in a brownie?