I would certainly go along with a Dell recommendation but if you want to save a bit more try Dell Outlet. From their FAQs
"Dell Outlet is the place to go to find great savings on some of the latest refurbished Dell Technology, already built and ready to ship. This is product which has been returned to Dell for a variety of reasons including cancellations and specifications changes. All products have been tested and repackaged to Dell Outlet standards. Dell Outlet also offers standard limited warranty coverage and the same excellent Dell service and support on our refurbished Products as we do on our new systems."
I recently bought a laptop for my son through this site and saved 30% on new price for what is to all intent and purpose a new machine. There is a very large range of constantly changing stock - its just a case of picking the one you fancy and in my case it arrived within a few days. Just note that you need to add VAT (15% before 1 Jan 17.5% after) and delivery(£21.08) to the price shown on the stock lists. An Inspiron 545 starts from about £250 incl VAT and delivery.
http://outlet.euro.dell.com/topics/g...b=INSPDT&s=dfh