Silent Storm: Gold Editon, PC – £1.47
Silent Storm: Gold Editon, PC – £1.47
To purchase digital games from Amazon US, use your UK Amazon account, and add a US billing address to your account. This address needs to be a valid US address, but nothing will be sent there, and you can access all your games through their website. Some card issuers may charge a fee.

Sadly this does NOT register on steam from amazon, as I have just discovered.
Apologies, thanks for letting me know. Shoot me an email via the contact form please.