Help / advise Perth mint proof

[Kussilver]

Looking for some advise from the more experienced members. I mainly stack for weight, picking up the odd sovereign as and when I can. I recently picked up this coin purely as a 1/4 oz gold. When I got home I did a little research, and found it is the 60 th anniversary of the queens coronation coin 2013. Perth mint 1/4 oz proof, with a mintage  of 1000 coins. 
I am not really into the numismatic / collecting side of stacking, so I am looking to sell this on to someone who may appreciate it more. 
I have added some pictures, as you can see the box is in a poor condition and the capsule is marked scratched. I took some pics with the capsule lid removed and the coin itself seems in good condition (at least to my untrained eye)
The main question really is how do I price this ? with the condition of coin and box and no COA. I found 1 for sale on bullion by post at £576, probably not a realistic price for private sale IMO. Is there still numismatic / collector value in this condition? 
 

let me know your thoughts, any help / advice welcome 

Thanks