Around 12 months ago I bought a Belkin modem / radio router from PC World. Six months later the power unit appeared to have died. I visited my local store the next day, checked it with a real person face to face, who confirmed the problem. Upon showing my receipt, I was invited to pick a new one from the shelf. I explained that I could do without the hassel of setting up again, and that it would be nice to take my original modem /router with a new power unit. I was told that this was no problem, and they checked that the old unit powered up ok.
30 minutes later I was back home and up and running, a very happy customer.
Not an unusual experience for me with this retailer.