2015 Tristan da Cunha £5 - 70th Anniversary of V.E. Day; [opgelost]

Hi guys,
I have a "Silver - Proof" 2015 Tristan da Cunha £5 - 70th Anniversary of V.E. Day five pounds coin, which I have already find in the Numista Catalogue, but I'm still not sure, if it's a "real" Silver Proof coin, or just a silver plated Cu-Ni coin, like the 2016 Gibraltar Half Crown?
If anyone can help me about this coin, I will be much appreciated.
Thanks in advance.
Gabe.

I would assume that the mass would differ - which one is it?

There are only two material issues : gold-plated copper and Silver

Citeer: "CoinCollector1243"​I would assume that the mass would differ - which one is it?

​This is the 2015 Tristan da Cunha V.E. Day £5 silver coin, but I don't know that, if it's an Ag.999 fine silver or a .925 highly polished mirror proof Sterling Silver, but I will find out.
Thank you very much.

Citeer: "Frenchlover"​There are only two material issues : gold-plated copper and Silver

​​This is the 2015 Tristan da Cunha V.E. Day £5 silver coin, but I don't know that, if it's an Ag.999 fine silver or a .925 highly polished mirror proof Sterling Silver coin, but I will find out.
Thank you very much.

Silver 0.925