sounds like you can buy anything you want (you don't need anything with spectacular performance) - and I'd suggest looking on Ebay for the best bargain than shopping in the high street; you'll find many clearance specialists with new and/or 'like new' refurbished kit, and save yourself some cash you can then spend on other stuff. Also you could check the outlet store on Dell's own site - always worth a look.
500 quid ($750) sounds like an awful lot for a laptop - if you don't require something with all the bells and whistles, and many manufacturers are selling entry level kit here in the States for half this price; although admittedly in the UK you'll need to multiply our prices by at least a third.
find yourself a model from last year (that was released 6 to 9 months back) and you'll save yourself some money.
not sure if this might work for you, but you can try it: <a class="postlink" href="http://www.dell.com/uk/dfh/p/" onclick="window.open(this.href);return false;">http://www.dell.com/uk/dfh/p/</a>
Inspiron 15R - N5110
Inspiron 15R - N5110
Processor: Intel Core i3-2350M (2.30Ghz, 3M cache)
Genuine Windows 7 Home Premium
4 GB DDR3 SDRAM 1333MHz (1 DIMMs)
Hard Drive : 500GB Serial ATA (5400RPM)
8X Tray Load CD/DVD Burner (Dual Layer DVD+/-R Drive)
Display: 15.6in High Definition (720p) LED Display with TrueLife
Intel HD Graphics 3000 with up to 1.6GB Dynamic Video Memory
English Genuine Windows 7 SP1 Home Premium (64Bit OS)
Wireless : Dell Wireless 802.11g/n + Bluetooth v3.0+HS Card
LCD Back Cover : Diamond Black Switch Cover [Switchable Lid]
6 Cell Primary Battery, 48W
for 300 quid!