Anti-aliasing issue after upgrade to Unity 5.0

Simple question, the image below displays the current state of my trees after importing in to Unity 5.0 from 4.6.2.

As you can see the tree meshes are visible for some reason. I've tried to edit all settings and I can only achieve disappearance if I turn Bill-Boarding and Fade Length both to their lowest values (5 and 0 respectively). This however is not a solution as these tree's are useless visually.

FURTHER: I believe this is an Anti-Aliasing problem. The problem worsens as you increase the Multi-Sampling amount in the Quality settings of the project. Disabling Anti-Aliasing fixes the problem entirely however I still don't believe this to be a correct solution?

Settings for the terrain below:

Anyone got any ideas?