Demo Content only partially imports

I’m trying to install the demo content for Unicon at this URL: http://2017.merewyn.com.au/

I’ve tried importing the demo content a few times but each time only a few pages and some of the images are imported, and then the loading symbol just spins and spins for hours.

I’m using a clean install of WordPress – theme install is all I’ve done – and I’ve reset WordPress between each attempt using reset-wordpress.

Wordpress is up to date and I’m using Unicon 2.4.1. There are no other plugins or themes installed, beyond what came bundled with Unicon. I’ve searched all the forums for help but none of the answers to similar questions provided a clear solution.

Ticket