Unfortunately, there are still a lot of shitty "frituurs" in Belgium that just fry bought frozen fries instead of the double fried freshly cut ones. Problem is, they get taken over by new owners very quickly (also the the barrier to entry the market is very low).
Although checking out the Google Reviews before a visit filtering by the Belgian names of the reviewers' is generally a good enough measure to go by.
For anyone in the UK looking for the same kind of mayonnaise that you get in Belgium, the closest I've found is this Polish one, available from Tesco or your local Polski sklep.
Although checking out the Google Reviews before a visit filtering by the Belgian names of the reviewers' is generally a good enough measure to go by.
But please, do try them with mayo!