Why is it important that you purchase a refurbished laptop, when you can buy a brand new one nowadays for only a little more extra expense?.
If you look at Ebay you will find a number of companies that sell refurbished and returns, usually with a full twelve months warranty. Just look for the Dell, Tesco, Amazon, Argos, Comet, PCW and franchise outlets who use the eBay website. You could also go direct to those companies own websites, to see if they have any refurbished units listed. Other companies can easily be located by a simple Google search like http://www.thelaptopcentre.co.uk