The thing is MoreMilesPlease, those that you linked on Amazon cost at least double what the kind I showed in the picture above cost. If you look again at the picture, you will see a price of $7.99, roughly 5 GBP.

It isn't about the money per se, it is about it being considered disposable and so you want to spend as little as possible on it. I'm guessing that the OP will probably opt for a cool bag or hard shell cooler as that is what is relatively easily available in the UK. But I'm also guessing the OP was looking for a 'styrofoam' cooler as in the picture above.

When you end a road trip in a rental car and come to dispose of a 'styrofoam cooler', you just break it up into pieces with your hands and dispose of it in a rubbish bin. If you have a hard shell cooler, not only can't you easily do that but there is just something 'wasteful' in throwing a perfectly good hard shell cooler in the rubbish. It just doesn't 'feel right' if you know what I mean. I know that if it were me ending a trip with a hard shell cooler, I would be looking to give it to someone to use rather than putting it in a rubbish bin. It just somehow would not be as 'disposable' in my mind as a simple styrofoam only cooler is. I guess it is a cultural thing perhaps.