This is an excellent deal for Qatar Airways which is one of six 5 star airlines in the world. I didn't realise this but Virgin, British Airways and even Emirates are classified as 4 star
Dates I put in were 27 November to 4 December 2010 but there are loads of dates available
There are also offers from other airports and to other destination as Qatar currently has a sale. I checked for this flight on Sunday and it was over £420
November and December are the best months to go to Dubai with temperatures of around 30 degrees rather than over 40 in the summer months
Just to add, you can get flights on Gulf airlines for £330 for that time of year but that is a 2 star airline. So the difference of around £33 is excellent value for a much better airline.