Voting appears to be an emotional response rather than a practical one.
The national percentages in that survey's results show a much more even spread with Labour [26%] ahead of the Greens and LibDems [21%] with the Conservatives [14%] and UKIP well behind.... sad that people tend to ignore what is being presented to them.
Perhaps all it shows is that people who take part in surveys [ie with a tendency to be more curious and more open to change?] are clearly left of centre.... and that people who write these surveys are too, because if it showed a national trend in the election, and it should if people voted more pragmatically, the party splits would be very different.