I'd suggest this:
Dell U2419H UltraSharp 24 Inch Full HD (1920x1080) Monitor, 60Hz, IPS, for £165 or so.
It comes colour-calibrated as standard, covers 99% of sRGB, and is an IPS panel.
You do lose the 16:10 aspect ratio--like most monitors today, this is 16:9 ratio.