Aircard 790s stuck on BigPond splash screen

Hello everyone,

I have an unlocked Aircard 790s which has the BigPond firmware on it.

I have been using it intermittantly for almost a year now here in the UK on the Lebara network, fairly trouble free.

I tried to use it this weekend and it would not boot up past the BigPond splash screen.
The only way to turn it off is by taking the battery out. I've tried starting it without a sim in and various other ways to see if I can get it working but no luck.

Can anyone help me fix it? Picture below of the screen I can no longer get past.

Thanks, Matt