It might also be worth looking elsewhere at the Eizo Flexscan range too, which are in the £260 region. Eizo make some of the very best monitors around in the form of the Eizo Colouredge models. Those are a bit above your budget (and mine for that matter lol) at £1k a pop and are aimed at professionals in the graphic design/printing industry, due to their accuracy in colour rendition and gamut.
I should imagine though, that you'll be satisfied with which ever manufacturer/model you pick. Just to throw more choices into the mix, my brother has a 27.5" Hanns-G monitor which I have to say, I was extremely impressed with.
http://www.ebuyer.com/202805-hanns-g...i-3ms-hz281hpb
£218, 1900x1200 resolution and 3.5" bigger than my Samsung monitor! I might invest in one, when funds are a bit more available lol.