Hello Twinsforheat,
I found a way to re-order the logos in the slider, and I wanted to share my findings with you.
Make your way to WP Admin -> GS Logos -> All Logos.
Hover over the logo you wish to change, then click “Quick Edit”
I believe that the logos are organized by the time of publishing, so if you change the published time to 1 minute before the previous logo, then it will automatically re-arrange the logos upon refreshing the page.
I’m sorry if that didn’t make sense, but I hope it helps you resolve your issue.
Best wishes.