Here is a link to my free UK paid surveys page http://www.online-paid-surveys.net/UK-free-paid-surveys.htm have had lots of hits and good feedback on it.
Yes, surveysavvy does have a good referral program, but I disagree with the just build a good downline statement. Building a downline is good, but you need to take surveys and be active in the paid market research arena in order to be able to build quality content to attract users to your site. Plus, the right survey panels have decent payouts, and are worth the time to take. Have you ever taken a surveysavvy survey? Easy $10 to $20 bucks for a 20 minute survey.