PC World have a voucher code for 20% off on Keyboards and Mice. Using this you can get the Apple Wireless keyboard for just £44.80. It's even less with quidco. It retails at £56.00 in the Apple store.
Add the code MAK20 on the payment page for the discount.
Description of the Keyboard:
"The incredibly thin Apple Wireless Keyboard sits on your desk surrounded by nothing but glorious space. It’s cable-free, so you’re free to type wherever you like — with the keyboard in front of your computer or even on your lap. Not only does the Apple Wireless Keyboard come standard with the new iMac, it’s perfect for any Bluetooth-enabled Mac."