They are offering a refund assuming a leather sofa would last 6 years. Is that how the calculation should work?
I’ve got some leather sofas in my flat which are now 10 years old and almost look new, in fact they look better than new when they were too shiny and smooth. I did claim on the warranty 5 years ago as the frame had split at the back, it was a known problem as the later ones had an additional leg in the middle and the guy commented that the sofas looked like they had just come out of the showroom.
I would argue a leather sofa should last >20 years but i don’t know if that can be applied to the calulation.
The mis-sold thing is a completely different kettle of fish. You had no way to know until they failed. The thing is you have had 6 years use out of them so I guess they can still deduct for use, but again would they only expect the sofa to last 6 years? Doesnt sound like they think much of their own sofas…