Loads of choice at this price range and you should be easily be able to get a decent 1080p screen closer to the £400 mark or even cheaper, for example;
Panasonic VIERA TX-40AS640B: last years model, specific for Currys/PC World for less than £300 at the official Panasonic Outlet eBay store. VA panel, highly recommended on
HDTV test, ?direct LED lit similar to the Samsung UE40H6400, active 3D. Not the best in terms on input lag so if you're plan on using it for console game then get a Sony Bravia instead.
Other options;
Samsung UE40H6400 £399 @ John Lewis
Link. Faster quad core for in menu and SMART stuff etc.
Panasonic TX-40CS520B £349 @ Richer Sounds
Link. 2015 range, no 3D, edge-backlit I believe and only two HDMI inputs.
Sony KDL42W705B Very good for TV for gaming if you can get hold of one for <£400.