How do I enable localStorage in Safari on iOS7?

How do I enable localStorage in Safari on iOS7?

When a web page loads javascript is able to write to localStorage, and read from localStorage. However once the page reloads or URL changes, all data stored in localStorage disappears. "Settings -> Safari -> Advanced -> Website Data" shows no data for the domain.

Is there a setting to enable persistant localStorage on iOS7?

(i'm not in Private Browsing mode, and this works in Safari on PC, Mac and iOS 6.1.3)

Many thanks.