Great Britain sovereign uniface George V

Hello, I came accross strange one sided coin, as I learned this is called uniface. The coin is Britain's, in nice golden colour eventhough the scan doesn't show that, plain edge, roughly the size of sovereign 21+ mm, with the portrait of George V. Any cunning thoughts what could it be?

Just compare the weight. If it's not comparable then your coin is PMD (Post Mint Damage).

Of course the weight doesn't fit, it's not golden coin but still the portrait is well-made, maybe some official try-out, attempted counterfeit or some sort of souvenir?

By that colour it’s a farthing not a sovereign... worth 960 times less in the old £sd system.

Edit: farthings are 20mm in diameter, halfpennies are 25.5mm. Either way the colour looks more like toned copper than gold to me.

No, the colour is nice golden but the scanner doesn't catch it well as I mentioned before. Of course I know it's not golden sovereign and neither farthing but what is it? Who was making such a "half" coins and why?