My understanding (and I could be wrong), is that no consumer has the absolute right to return an item. Once the item is purchased, the retailer does not have to take back the item.
That is correct in the context of going to the shop in person and buying an item.
Defective goods on purchase, can be exchanged or refunded.
DSR and Hire Purchase (distance or in person) are covered by the "cooling off" period for contract cancellation.