Member Data Exporter Addon not exporting all users

To start with, I’ve recently taken over a site that was put together by someone with limited/no knowledge of implementing WP. I’m not much better, but trying to make the most of it. The site in question is a replacement site for a bespoke site that had 5000+ members on it. All of that data was exported and imported into Simple WP Membership. This is where some of the issues started to crop up. On the previous site, it was used as the businesses core membership database. Many of their members never logged into the website as they provide real world benefits that don’t require using the website. This meant that when the data was imported in, there was no Last Accessed date for several thousand members (it shows 0000-00-00 00:00:00), and there is also no Access Starts date.

When I run the data exporter and set the Access Start Date Range to nil on both start and finish, I only get ~50% of the members.

Is there a way to force it to export everything regardless of dates?