Adobe Spark issues - loading and logo

I'm finding Spark an absolute nightmare. It's so slow and at the moment won't even open a project, it just stays on the loading page. I need to change the logo that appears in the bottom right hand corner - does anyone understand where this is pulled from. It doesn't seem to be the primary logo (in branding) so is it the first secondary one? I've changed the secondary one now, but can't open the project to see if this has now populated.

Help of any kind appreciated.

Thanks