I applied through a staffing agency. The process took 4 days. I interviewed at YouGov (London, England) in Mar 2017
Interview
There were two interview stages. I didn't have to go through any tasks or practical tests. Both interviews were 2 v 1 which lasted about 30-45 mins. If you prepare for typical interview questions then you should be fine.
Interview questions [1]
Question 1
Why join YouGov, Where do you see yourself in 5 years time, Any other questions we should of asked.