I know it depends on the person / property, but i would seriously consider getting a Sunroom / Sunlounge instead of a conservatory. I am at present deciding how to go about putting a proper tiled roof onto my conservatory to make it into a Sunroom. It's for all the usual reasons, too cold in winter, too hot in summer, too noisy when it rains etc..
Saw a flyer recently for a company advertising a 2 day sunroom, alas I cannot remember the name, looked the business though. No price was given either, but definately look into a price comparison between the 2 systems.
Cheers