I do online surveys as well, there was a sign up deal from the BA Executive Club that gave you bonus points on the first survey and it's easy to collect 2000 points a month doing them
I just used AVIOS to upgrade to Biz for the USA, cost me £1200 return incl. Just used Tesco Clubcard points , Clubcard credit points plus miles from previous trips etc. Everything I have collected would have been stuff I would have done anyway so it's getting things for free