How to access Addon .zip files after using new v3.2.0 built-in Addon purchase mechanism

I’ve just purchased an Addon via the new v3.2.0 built in Addon purchase mechanism. I’ve got the license key OK, but “Install” doesn’t work. I’m almost certain that this is because I have enhanced security which doesn’t allow WordPress to write to the plugins folder.

In the manual it says that this isn’t a problem because you can unzip the relevant .zip file and upload the relevant folder via FTP. I know how to do this, but I can’t figure out how to now get access to the relevant Addon .zip file.

I’ve lodged an inquiry via Paddle support but I thought that I would ask here as well.