This isn't accurate (from what I understand).
You have 7 working days (not two weeks) and that time begins the day after you take delivery. Not the day of delivery.
You do not need to send the item(s) back within those 7 days, instead you must inform the company of your *intention* to return them.
Additionally, you do not have to return the item(s) yourself, though in fairness most people do

The law doesn't specifically say you have to return them, just make them available for collection.
Lastly, the goods do not have to be in a re-sellable condition to return under DSR. However if the goods are damaged, the company has the right to charge you a fee.