Bought a TV from Argos instore - Disappointing picture quality can I return?

Bought a Philips TV from Argos a couple of days ago in store, really disappointed with the picture quality, not as good as my 6 year old Toshiba. What are my rights to return it for a refund? Will they except it back or does it depend on store? Has anyone returned a TV back to Argos for the same reason?