Following on from my previous post, the 4.3.6-0718 beta worked perfectly for the cell connection, just hitting Auto and it connected. Checking the setting under the Manual button, it had set the APN correctly to “Internet”.
But, after upgrading to 4.3.6-0720, and powering on I’m met with the banner: SIM card not registered. Going into the Manual settings and entering Internet (BTW It’s really difficult on an iPad to manually enter the APN), because the field was empty this time, it still doesn’t connect.