Surveyhead surveys I find have a 90% throwout rate so I was pleased to finally have enough points to redeem a voucher, the voucher being a £10 Shoebuy.co.uk voucher. Now I wouldn't recommend redeeming this voucher and keep going till you get your £15 Amazon Voucher.
Shoebuy products tend to be double the price of something exactly the same that sells on e-bay. With this in mind, I decided to sell the voucher on e-bay. It sold for the princely sum of 30p which left me with 7p profit after deductions. I've given up with Surveyhead now, and Gratispoints are pretty poor too with a high throw-out rate.