Very good price as elsewhere this is: -
SHD Technology Ltd £45.93
PCWorld Business £42.32
Onestop Shop £45.39
S4 ICT £51.13
and next cheapest I can find is £15.80 @ Amazon
Wireless freedom, optical control, optimal value
Get the reliability you expect from Microsoft hardware at an extraordinary value - with the Microsoft Wireless Optical Desktop 700. This keyboard and optical mouse combine the freedom of wireless with the control of an optical mouse with scroll wheel. Plus, it's easy to use - just plug in the receiver and start typing.
Less desktop clutter
Control your media activities with the touch of a button.
Easy to Set Up and Use
Just plug in the receiver and start typing.
Compact design saves desk space.
Wireless Optical Mouse
Enjoy wireless freedom and comfort
Move through your documents quickly without having to click the on-screen scroll bar.
Comfortable design created for either hand.
Optical sensor delivers greater accuracy and control.