If you dial up
www.google.co.uk and then Google 'refurbished computers'
You will bring up pages of ex lease machines, usually W7, may or may not have Office, 4GB RAM etc. I got a brand new 15.6" HP laptop for A$307.00 never been used, still had protective plastic on it, that was a very lucky break, have had several Dells, all work well for anywhere from GBP250.00 up. Some lease machines have worked a normal life, some have sat and gathered dust, you take pot luck but Dell refurbished are in pretty good order. There is a company that sells refurbished in UK that also sells '2nds', never used, slight damage, older model, just can't remember the name of the firm now. BIL got a top end Toshiba for GBP450.00