Fire HD Tablet: Age verification settings for Amazon Prime do not work

[skroop]

Received my new Fire HD 8 this week and I cannot get the Amazon Prime age verification settings to work on it - they work fine when using Amazon Prime in a Chome Web Browser on my PC (i.e. I am prompted for a PIN to access age restricted content)

Does anyone know if this is just a fault with this device or across all the Amazon tablet range?