many Firefox bookmarks not syncing via iCloud

Guys,

I have set up Firefox 24 on a Windows 7 PC to sync with Safari on iOS 7 on an iPhone 5. This uses iCloud Control Panel 3.0 for Windows and Apple's Firefox extension iCloud Bookmarks v1.0.18+.

I have at least 10,000 Firefox bookmarks. Many of them (including the (complete) contents of many bookmark folders) do not appear as Safari bookmarks.

Do you know what might be the problem? Do you know if there is a limit to the number of bookmarks which may be synced?

I would be very grateful for a reply!

Best regards,

Cian Buckley