@RetroDan, you have an AudioSource component yes? I don’t see it shown in your screenshots, other than the code reference to it, which I notice is in blue which may suggest it’s referencing the AudioSource class not an instance of it…
… ah, ignore, I’ve just seen that it’s a Static method… sorry…
Update
Found this, it’s from the end of last year, but there might be something useful in it…
http://forum.unity3d.com/threads/unity-5-2-0f-no-sound-function-audiosource-playclipatpoint.354364/
The posts which suggest they have it working mention setting the position to that of the camera. There is also mention of the spatialBlend but I don’t know whether you have a 2D/3D game going on here…
I’ve not used this specific method myself, I have a little soundboard example which plays a clip on a key press, that has an AudioSource as a private member within the script, instantiated in the Start() method where it grabs a reference using GetComponent etc. It’s just a cube in a scene, nothing fancy… happy to share if it’s of any use.