A bit more than £200, but I use a Dell UltraSharp U2717D 27" (the newer U2719D is about £300). Really great for CAD work, low reflectivity, really thin border if you want to double up on the screens. Good connectivity with USB hub built in for your 3D SpaceMouse (if you have one). Would really recommend it.
Specs:
"The Dell UltraSharp U2717D monitor has an active matrix, thinfilm transistor (TFT), liquid crystal display (LCD), and LED backlight. The monitor features include: 68.47 cm (27-inch) active area display (Measured diagonally) 2560 x 1440 resolution, plus full-screen support for lower resolutions."