I think this is a misprice from M&S.
They've not got this as a special deal or anything but the price is brilliant.
The KDL-32W5500 is 499
The KDL-37W5500 is 499
The KDL-40W5500 is 750
I think the 37 is supposed to be 599.
It's 716 at Amazon.com.
The W5500 has the BE3 engine and 100hz (the V5500 is BE3 with 50hz, the S5500 is BE2 and 50hz)
I was really tempted except the in-store feed to the TV was terrible and I couldn't tell how much better this tele was from this deal... http://www.hotukdeals.com/item/663705/sony-bravia-40-kdl-40v5810u-full-hd
I asked the staff for a better feed and they said they couldn't change it (they were helpful but said it's company policy not to change the feeds).
I think this is a great TV for under £500. I've not seen a better TV under £500 with a 37" or bigger screen.