How about something like the The EeeBox PC EB1012P ?
Processor Manufacturer: Intel
Processor Type: Atom
Processor Model: D510
Processor Core: Dual-core (2 Core)
Processor Speed: 1.66 GHz
64-bit Processing: Yes
Hyper-Threading: Yes
Chipset Manufacturer: Intel
Chipset Model: NM10 Express
Standard Memory: 2 GB
Maximum Memory: 4 GB
Memory Technology: DDR2 SDRAM
Memory Standard: DDR2-800/PC2-6400
Total Hard Drive Capacity: 320 GB
Controller Type: Serial ATA
Graphics Controller Manufacturer: NVIDIA
Graphics Controller Model: GT218
Graphics Memory Capacity: 512 MB
Graphics Memory Accessibility: Dedicated
Ethernet Technology: Gigabit Ethernet
Wi-Fi: Yes
Wi-Fi Standard: IEEE 802.11n
HDMI: Yes
Operating System: Genuine Windows 7 Home Premium
Operating System Architecture: 64-bit
Color: Black
Height: 7.0"
Width: 8.7"
Depth: 1.1"
Weight (Approximate): 2.43 lb
I'm sure if you shop around you may find one for around £250ish

just an idea. I know OCuk doesn't stock them.