The specs looks very impressive
I have u2711 and it is great once calibrated; 24" is not that much smaller
It's not much smaller, no, but a 24" screen is usually 1920x1200 pixels whereas the U2711 is 2560x1440 pixels, so it's MUCH higher resolution, and that DOES matter. Toolbars and menus are much smaller in comparison and leaves you much more room to work. Besides.. it's not much taller than a 24" screen but it's considerably wider. Comparing them side by side... well.. there's no comparison.
The monitor is THE most important part of any digital darkroom and the ONLY component that has a direct influence of the quality of your images. Do not skimp on the monitor.
Another thing to consider is calibration. There's little point in an expensive monitor if it's not calibrated.
I use an
AOC i2353 which I got from PC for about £150 (there's a 27" version for £199). Never had a problem with it, never had to calibrate it and my prints from Loxley always match the monitor.
I'm sorry.... but the 27" version will be 1920x1080, and at that size, the pixels will be huge. Also... you get what you pay for. It will be a cheap TN panel.. almost certainly a 6 bit panel, and if you're happy with it.. no offense but you've clearly never seen a decent screen once calibrated. If your prints from Loxley match your screen it's luck... nothing more.
Re: The Dell U2711. It has a very aggressive anti-glare coating which can "sparkle" when moving your head round and looking at highlights. It's not a deal breaker, but it's noticeable.
Shiny screens are generally not a good idea due to reflections. There's a very good reason all high end screens use an anti-glare coating. All High end stuff from Eizo and NEC use it.. why do you think that is?
Another SUPERB choice in your price range (JUST.... you may have to add a bit.. but worth it... check prices though as NEC stuff has just had a price increase) is the NEC PA271W. This has a beautiful LG IPS panel and does not suffer from the "sparkle" the Dell does.
I would recommend the NEC PA271W over the Dell U2711, but if the price hike recently has pushed it over the £750 mark I'd go for the Dell.
Incidentally... I'm recommending from experience... not guesswork and browsing web sites.