Try their web sites www.dixons.co.uk and www.pcworld.co.uk. Both can be agonisingly slow (and we're on a v.high speed link) and dixons logs you out whenever it feels like it. Not good.
Now try www.comet.co.uk, it's faster and much easier to use. Prices similar to dixons though.
But now try www.empire-direct.co.uk , fast, easy to use web site and prices that generally beat Dixons. I spent several hours visiting stores and looking at the web when spending £1200 on goods the other day. empire direct were head and shoulders above the others and you can order by phone not just by 'net.(Saved £200+ by using them and not Dixons/Comet). Not sure who owns them though? Part of Empire Mail Order maybe?
Dixons need to get their e-commerce act together PDQ if they're to compete against comet and empire IMO. However, I notice that they don't mention e-commerce in their finals (at least not that I see). Maybe they don't see it as important? If they do then they should perhaps spend £50K or so on new servers.