I’m afraid you can’t collide ‘with’ particles, we don’t create any kind of spatial structure for them that would enable this. You will need to create some collision shapes to go along the trail and use those for collision.
Cheers James, I figured out I could fire an event then get the events location in my Blueprint, then I’m creating (currently) a static mesh so I get both collision and it affects the navmesh which is set to runtime dynamic. Probably going to look at simple box collision ‘at some point’