Problem with 1920 Gold Sovereign

Hi,
A friend of mine asked me, if I can find some information about his coin. It is a 1920 gold Sovereign. He says it is genuine, the dimensions are what they have to be. But the problem is the mint mark - here isn't any. No mint mark on Sovereign (as far as I know) means London mint, but 1920 Sovereigns are struck only by Sydney, Perth and Melbourne mints. At least that says Google. Do you have any Ideas? It doesn't look like the mint mark is worn off. Maybe the coin is fake. Here are some pictures.


Thanks

I can't tell from your images if there is a MM on your example, but your assessment is correct. There should be a "P," "M," or "S" above the date, and if it's not there, it's probably a fake coin.

It could still be gold, but a "jeweler's copy" created to show off a local goldsmith's skills.

Thank you very much