How about a very lazy solution?
Got to eBuyer and get a prebuilt Asus Aspire M1930 for £229.32
http://www.ebuyer.com/279903-acer-aspire-m1930-desktop-pt-sgce9-005Product Description
Processor
Intel Core i3-2100 3.1 GHz
3MB Cache
Memory
4GB DDR3 RAM
DIMM
Hard Drive
500GB SATA
Optical Drive
DVD Writer
Software
Operating System: None
Display
Monitor Not Included
Graphics
Intel GMA X4500
Input Devices
PS/2 Keyboard and Mouse
Networking
LAN: 10/100/1000
Dimensions
Width 180 mm
Depth 401.8 mm
Height 379 mm
Weight approx 13kg
Interfaces
Front
Two USB 2.0 ports
Headphone/microphone line-out jack
Back
Four USB 2.0 ports
PS/2 keyboard and mouse ports
Headphone/speaker line-out jack
Microphone-in jack
Line-in jack
Ethernet (RJ-45) port
D-Sub VGA port
USB module with four USB 2.0 ports
Expansion
Multi-in-1 card reader
Warranty
1 Year Manufacturer Warranty
Or maybe an Asus Aspire X1900 for £281.55
http://www.ebuyer.com/261797-acer-aspire-x1900-desktop-pt-sdve2-003Product Description
Processor
Intel Pentium Dual Core E5800 3.2GHz
Memory
3GB DDR3 RAM
Configuration 2GB + 1GB
Hard Drive
500GB SATA
Optical Drive
DVD Writer
Software
Operating System: Genuine Windows 7 Home Premium
Adobe Reader
eSobi
Microsoft Office Home and Student Edition 2007 Trial (Service Pack 2)
Microsoft Works
Windows Live Essentials
Adobe Flash Player
Google Setup
Google Toolbar
Netflix shortcut
Skype
Acer Arcade Deluxe 4.0
Nero 9 Essentials
eBay
GameZone
Security
McAfee Internet Security Suite Trial8
MyWinLocker
Display
Monitor Not Included
Graphics
Intel Graphics Media Accelerator X4500
Input Devices
PS/2 Keyboard and Mouse
Networking
LAN: 10/100/1000
Dimensions
Width 100 mm
Depth 371 mm
Height 265 mm
Weight 8kg
Interfaces Front
Multi-in-1 card reader
Five USB 2.0 ports
Headphone and microphone line-out jacks
Back
Two USB 2.0 ports
PS/2 keyboard and mouse ports
Headphone/speaker line-out jack
Microphone-in jack
Line-in jack
Ethernet (RJ-45) port
D-Sub VGA port
Expansion
PCI Express x 16 slot
PCI Express x 1 slot
Warranty
1 Year Manufacturer Warranty
Or more up the upper end of your budget there's something like eBuyers own "Value Desktop" for £295.49
http://www.ebuyer.com/271601-extra-value-desktop-pc-7873-1044Product Description
For a visibly smarter PC experience, look for the 2nd generation Intel Core processor family. These new processors feature improved adaptive performance that adds speed when you need it and built-in visual capabilities for a better PC experience you can see. We call that visibly smart performance. You’ll call it Amazing!
Perfect for office applications, but outstanding for entertainment, this new desktop range delivers multi-tasking through the Intel® Hyper-Threading Technology and our Core i5 and i7 models automatically speeds up (overclocks) your PC when you need it with Intel’s new Turbo Boost technology.
Please note that this desktop PC does not come with an operating system. Ebuyer recommends using genuine Microsoft Software and is Windows 7 compatible.
Processor
Intel Core i3 2100 3.1GHz
SandyBridge
3MB Cache
Memory
6GB DDR3 RAM
Expandable to 16GB
2 x DIMM slot
Hard Drive
1TB SATA II
Optical Drive
DVD Supermulti
Software
Operating System: None
Display
Monitor Not Included
Input Devices
Keyboard and Mouse Not Included
Networking
Network Interface: 10/100/1000
Dimensions
Width 180 mm
Depth 450 mm
Height 360 mm
Interfaces
1 set 5.1 channel Audio jacks (3 jacks)
1 x PS/2 keyboard port
6 x USB 2.0 ports
1 x RJ45 LAN port
1 x VGA port
1 x DVI
1 x HDMI
Expansion
1 x PCI-e x 16 slot (Free)
2 x PCI-e x 1 slot (Free)
1 x PCI Slot (Free)
4 x Sata II ports (2 free)
Warranty
1 Year Manufacturer Warranty
Happy shopping fella
