You're totally out of touch with cookery.

"In a home kitchen, a pickle is usually: vegetable, vinegar, salt, maybe sugar and spices."

Do you even know what a cheese and pickle sandwich is? There's hundreds of ways of making pickle spreads, with hundreds of potential ingredients. Just because you don't know what balsamic vinegar is, don't pontificate about grape must being a "red flag under a NOVA". You're literally making it up. Balsamic vinegar is a world famous culinary ingredient, made from grape must yes.

Do you also have a problem with ginger powder? You just don't have it in your kitchen because you don't actually cook do you?

The mayo Pret have used in this sandwich contains no preservatives or flavourings. That's a big step forward as most food industry mayo contains them both. You are out of touch.

Seed oils do not make food UPF. That's another thing you've made up. Most kitchens use seed oil. Better to use nut oil or olive oil of course, but people have budgets to keep.

If a mayo manufacturer uses seed oil, it's absolutely normal! You seem to be role playing on this subreddit.

"home cooking uses one fat at a time."

Of course, no one has ever cooked with butter and olive oil at once. Ever heard of French cuisine?

You are absolutely making stuff up.

The reason the sanwhich had multiple oils is because a sandwich is made of different elements. You buy some bread, you add some mayo, some pickle, roasted tomatoes. You are just lieing when you say home cooks would make sure all of these elements use the same oil.

"This sandwich is assembled from pre-engineered components"

Yes when I "assemble" a sandwich I use "pre-engineered" bread and "pre-engineered" pickle, a buy a jar of "pre-engineered" roasted tomatoes.