I would never buy anything from DSG group, Dixons/Currys/PC World after all the bad experiences by myself and friends and relatives.
They consistently appear at the bottom of many surveys and have been taken to court frequently by Trading Standards as well as customers.
But beware, there is another one, viz; "Best Buy" appearing here from the USA and they have a similar reputation over there but have only just started here.
Just wait and see.
I have never had any problems buying from Amazon or John Lewis and will continue telling friends about them, and they are usually cheapest as well, taking into account customer service and extra guarantees free.