I am trying to create a 2D platformer game with collision, however a lot of the sprites are green and because of this I can hardly see the collision outlines, is there anyway to change the colour of the colliders in the editor from green to any other colour, I have searched online and cannot find any answers.
You can change the colour of collider outline in the editor for at least 2D colliders (which seems to be your case) by going to their Physics settings (not into Editor Color settings). This is per project setting, but at least you can do it.
Go to menu: Edit/Project Settings/Physics 2D
Then change the Gizmos / Collider Awake Color: