Dell and PC World
The reason that PC World would have advised the purchaser to contact Dell is that they don't hold stock of spare parts from the manufacturers - so any replacement keyboards etc will have to be ordered from said manufacuturer. Now although PC World sell Dell machines they don't provide any support - Dell do, so any customer with any fault with any Dell machine has to call them for help.
I think that the person that got the Logitech keyboard from PC World got a good deal!