I'd consider combining the following with the barebones system you found:
£20 DVD-RW DL: http://www.amazon.co.uk/Liteon-Ihap3...dp/B001GT2NZO/
£58 CPU: http://www.amazon.co.uk/exec/obidos/ASIN/B001ENB1FA/
£29 RAM: http://www.pcwb.co.uk/catalogue/item/CRUC012 (also avail for £33 at Amazon)
You'd need to have the 160GB HDD lying around. If you're going to buy a new one, it doesn't make much sense to go smaller than 640 GB (£54). Even 1 TB drives can be had for just a few more bills (£82), and you may find that the Samsung 1.5TB drive is the cheapest per GB (£119).
£20 DVD-RW DL: http://www.amazon.co.uk/Liteon-Ihap3...dp/B001GT2NZO/
£58 CPU: http://www.amazon.co.uk/exec/obidos/ASIN/B001ENB1FA/
£29 RAM: http://www.pcwb.co.uk/catalogue/item/CRUC012 (also avail for £33 at Amazon)
You'd need to have the 160GB HDD lying around. If you're going to buy a new one, it doesn't make much sense to go smaller than 640 GB (£54). Even 1 TB drives can be had for just a few more bills (£82), and you may find that the Samsung 1.5TB drive is the cheapest per GB (£119).