THE WEIGHTING GAME POPULUS POLLING Which party do you identify with? Unweighted UKIP 219 = 11% Weighted UKIP 20 = 1%
— General Election (@UKELECTIONS2015) September 25, 2013
The information can be found on table 12 and it seems the results are skewed towards none when they readjust the information.
Maybe http://ukgeneralelection2015.blogspot.co.uk/p/real-votes-not-opinion-polls.html could help them see that UKIP are getting a lot of support and it can't be weighted away.