There’s no substitute for ……

Heinz Tomato soup
Tunnocks Caramel Wafers
Kellogg's Crunchy Nut/cornflakes/rice crispies
L'Or Intense instant coffee

A really good slice of Black Forest Gateau with loadsa cream, deep dark chocolate and juicy boozy black cherries. Scrumptious.

Mollygo

Hate to disagree with Which? Tesco’s own tomato soup tastes good, but it doesn’t taste like Heinz tomato soup on a blind testing.

Oh well.maybe our taste buds are less sophisticated than they used to be, but it pleased us!

Kelloggs Coco Pops
Hellmanns Mayo
Cif bathroom cleaner
Daddies sauce
Semi skimmed milk
Domestos
Fairy liquid
Utterly Butterly
Heinz salad cream
Colemans mustard
Crisp n dry oil
Bournville cocoa powder
Homepride flour
Tetley tea

Daddie's Brown Sauce, better than HP in my opinion, and own brands come nowhere near.

Anchor butter.

Then I will stick with marmite.

Hate to disagree with Which? Tesco’s own tomato soup tastes good, but it doesn’t taste like Heinz tomato soup on a blind testing.

Blossoming

Heinz tomato soup, especially when I’m poorly. I know it’s a ridiculous price but no other tomato soup will do,

Which? said that Tesco's own tomato soup was s good as Heinz, so we tried it and it is! And it's about half the price.

Never thought I could find one as good, so it was a real surprise.

Marmite

Green and Blacks cocoa

Bonne Maman Jam (unless on very occasional trip somewhere people have made wonderful "home made".

M n S formula extra rich night cream

Bio-oil (can be found cheap on websites not in supermarket)

Olive oil, marmite, muller kefir

Marmite is a brand one of my favourites. Marmite and Bovril I have tried alternatives but they just don’t compare.
Wilkins lemon curd apart from homemade it’s the best but I have to buy it on line now.
John West tuna other brands taste odd.
Nescafé Gold old fashioned but my preference not into fancy coffees.
Delamere Goats butter better than any so called butter spreads that are fake.

my branded items are

haywards pickled red cabbage
branston fruity sauce
warburtons blue bread

the cabbage i buy 12 jars in my monthly shopping.

I used to think no other cocoa but Bournville. Then Tescos stopped having it, I was forced to try their own make.

Liked it better, and £1 cheaper.

I speed read it too Blossoming!
So, sweetex sweeteners, Worcestershire sauce (as Casdon said), Nizoral shampoo and that’s about it.

M0nica it’s all about the brands. The OP says “Have you got any ‘no substitute’ brands that you really don’t want to live without?”

Heinz tomato soup, especially when I’m poorly. I know it’s a ridiculous price but no other tomato soup will do,

The OP mentions brands. I thought Marmite was a brand

I’ve just thought of another two -HP sauce and Lea and Perrins sauce, nothing else I’ve tried tastes the same at all, they are all too sweet.

I have only ever liked Branston Pickle - no other make of pickle. But Mr R once picked up a jar of smaller diced BP and I found I liked that better.
I also only eat Royal Gala eating apples.
Other than that I am not fussy!

Fresh pesto as opposed to that yucky stuff in jars

New potatoes and other veg harvested from your garden and cooked/used within a couple of hours.

I thought it was about the brands!

Hellmans
PG Tips
Nairn porridge
Andrex
Kleenex
Cadbury's wholenut

Definitely Marmite for me too. I have tried various 'own' brand substitutes over the years, but it's got to be the original. I buy it in big tubs from Costco.

Bread. My main comfort food. I need to eat less of it and manage this by only buying 100% wholemeal which I like less.