There's a lot of two-way BS here.
Am I going to NOT go to Tesco just because they don't have Marmite or whatever ? Nope.
I import wine from France, properly, not load up the car in Calais ! A year ago I was buying wine at 1.35 = £1, now at commercial rates it would probably be around 1.09 or thereabouts. Without a doubt my prices will go up on my next imports.
But, the stuff in question here supposedly is made in the UK, but then maybe not. Remember that HP sauce is now made in Holland

Everyone wants to make money, Unilever, Tesco, me, everyone. Tesco are well known for stongarming and even bullying suppliers, Unilever are just huge. I'm not taking sides here, it's just not that clear or even that important to Joe public. I shop everywhere, spread it around, Lidl, Aldi, Tesco and even Morrisons, and of course I try to buy in my local shops as much as possible. Where I live local shops struggle, it would be a bit of a disaster for the town if Tesco or M&S were to close down, not so much if Lidl or Aldi did as they are a bit out of town and not big employers.
So, an interesting story in progress. let's see what happens