There are plenty of good deals here, if Orange is your brand. Delivery is free. For another Orange dealer try Freedom Phones . The site design is cute - you navigate by pushing buttons on a mobile, but it works. There are reviews and ratings of 60 different phones.
Delivery is free and they have various price promises.
A quality site. Beyond 2000 Sells phone accessories and spares. There are links to the sites run by all the major networks. Delivery generally takes 2-5 working days. If you've already decided on the network you're going to use, you could buy direct from, say, the Orange or Cellnet sites.