Hi Richard,
A new Sharing Cart ver. 3.5 is now released on the Plugins Database: https://moodle.org/plugins/block_sharing_cart. Version 3.6 coming soon. Also there is a new github for reporting issues. Sorry please re-enter any previous issues at this new github: https://github.com/donhinkelman/moodle-block_sharing_cart Thank you very much for your patience.
Don