Not just karrimor.
I have been through almost exactly the same dilemma when my (at least) 25 year old 35 litre Berghaus rucksack just fell apart. That thing had been around the world with me, dragged up and down everywhere, it was just brilliant. Then I had to find another - No chance.
The Berghaus back then was (as said above) a far cry from the rubbish available today. Everything now is full of 'features' that I don't need or want and the materiel that they're made of seems so flimsy. I wanted a simple rucksack, one huge zipped/flapped main storage area, two zipped/flapped side pockets and a small zipped pocket on the top for my passport, all made with a super durable fabric. Forget it.
I bought a Deuter rucksack (via a recommendation) that was so bloody fussy with features that it soon disappeared via ebay. I then bought an Alpine Lowe rucksack which I only kept for a weekend before taking it back. I'm now using a Millican rucksack which is NEARLY simple and hard wearing enough, but the main clasps to close the compartments are poor so I wouldn't recommend them.
Maybe ex Army/Swiss Army whatever ?????
Edit - I forgot about the Mountain Warehouse one that I bought. I think that I took it back the same day that I bought it. Fussy fussy fussy, bits of elastic all over the place, daft pockets and straps that I would never need. Crap zips n'all.