The Sony one would the choice for me at exactly £400.
If you can stretch a bit more i'd pick one with a 5 year guarantee. Saying that i have bought about 60 TV's over the past 15 years for work and only had 2 failures. One plasma was smashed (so not exactly a failure) and other was a rear projection which kept failing and eventually John Lewis gave me cash back to take it away and stop fixing it!
Saying that i still try to get a 5 year guarantee included in the price where poss. Which means I usually buy from Richer Sounds, John Lewis and Currys.
Also keep an eye out on Hot Deals UK. eg Sainsbury's have been selling TV in store really cheap and hence John Lewis have been price matching and selling great TV's with 5 year guarantees for good prices.
But if all that is too much hassle. The Sony