I think that price matching only relates to retail stores and not to match internet prices, I think Dixons is just internet now.
Have a look though at this site
http://www.washerhelp.co.uk/buying-washing-mac hines.html
He definately rates John Lewis as the best place to buy from but you should also look at what he says here
http://www.washerhelp.co.uk/reviews/miele-over view.html
about Miele.
They are much more expensive but you get a free 5 or even 10 year parts and labour guarantee depending on the model.
If you bought a different brand and a warranty of that length (assuming you could find one!) it'd probably cost you about the same