@Sideorderofchips
Salt and vinegar quavers
Prawn cocktail quavers
You're in luck, I saw an ad for this the other day saying they are bringing them back (possibly only short term though but better than nothing!)
I'll second the Brannigans crisps comment upthread, the mustard ones were super strong but great. Crisps today are so flavourless!
I've thought of another few for me:
Vichy face scrub. They probably stopped selling it about 20 years ago, it was amazing stuff though.
Also I used to love Nicky Clarke Hairomatherapy shampoos and conditioners. They used to make my hair smell lovely (I had very long swishy ringlets in those days and people would often comment on both how nice my hair was and how wonderful it smelt 
)
On rare occasions as a teenager I was sent to Bejam to buy a couple of things while my parents did the 'big shop' at the supermarket next door. One time I used my initiative and bought some little potato shapes. They were like a croquette, but spherical, about the size of a sprout and not in breadcrumbs though they had some sort of coating. They were bloody lovely, even my parents agreed and after that we bought them on and off for years. Then Bejam became Iceland and the little potatoes were no more 