came up with the following, except for a gfx card, as marine said, worth going 2nd hand , maybe 260gtx/460gtx, you could check members market and see whats around , new your looking at £100 ish for something like a nvidia 450 or ati 6770.
Intel Core i3-2100 3.10GHz (Sandybridge) Socket LGA1155 Processor - Retail £94.99 (£79.16)
Microsoft Windows 7 Home Premium SP1 64-Bit - OEM (GFC-02050) £79.99 (£66.66)
MSI H61M-P23 Intel H61 (Socket 1155) DDR3 Motherboard **B3 REVISION** £44.99 (£37.49)
Corsair Builder Series CX 430W V2 ATX '80 Plus' Power Supply (CMPSU-430CXUKV2) £35.99 (£29.99)
Samsung SpinPoint F3 500GB SATA-II 16MB Cache - OEM (HD502HJ) £32.99 (£27.49)
Cooler Master Elite 330 Midi Tower Case - Black £29.99 (£24.99)
Kingston HyperX Blu 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (KHX1600C9AD3B1K2/4G) £23.99 (£19.99)
Samsung SH-D163C/BEBE SATA 16x DVD-ROM (Black) - OEM £12.98 (£10.82)
Sub Total : £296.59
Shipping : £11.75
VAT : £61.67
Total : £370.01
