Premium version wont install

Hi,
I installed the free version of S2W and checked it was able to pull some products through from Shopify. Happy that it was working I paid for the upgrade, expecting that it would use the software already installed. Clearly it doesn’t and needs a new version installing and it didn’t like that, part way through the installation process WordPress through the following error:
“The uploaded file is not a compatible plugin.”
“An error occurred while installing the plugin.”

I thought maybe it doesn’t like the full version and the free version being installed at the same time so uninstalled the free version and tried again, but with the same error.

What do I need to do to get this working?