Grease Pencil Animation Vertex Problem

I’ve recently gotten into Grease Pencil animation on Blender v2.79 so I’m pretty new to it, I have a rough animation of a witch walking along a tower in tune with the camera, however I want to move the whole layer so it matches the movement with the camera panning around the tower.

I’m having no issues so far except whenever I try to select the whole grease pencil frame to position the drawing elsewhere, the drawing only selects one single vertex to pull out when I want to move the whole object layer, this is in Edit Mode and I’m using the dope sheet. (Example below)

How do I need to fix this? I would greatly appreciate any help, I have being looking on youtube vids and they never seem to have this problem, unless it’s something absurdly simple, Thanks!

Gemma