Issues sharing content packs with groups

To rule that out I've now made all users within the groups involved Power BI Pro licensed (although some still have Business Premium rather than E3/5). 

I have also gone back to the group and added the users via their individual email addresses rather than the group email as the documentation suggests that isn't working yet (https://powerbi.microsoft.com/en-us/documentation/powerbi-service-create-a-group-in-power-bi/).

I still cannot however access the content pack shared with 'Group 2' though from within Group 2 though.