They have no obligation to refund you. Under your statutory rights, you can only demand a refund if the product is faulty, or dosen't perform the function(s) it is advertised as having.
However, to please their customers, big retailers like Virgin do offer refunRAB on a 'not wanted basis'. Not being wrapped shouldn't be a problem (although I know online retailers like the shrink wrap intact).
It'd do no harm asking, i would imagine they'll give you your cash back.