The behaviour I am seeing when I upgrade to 3.1.1. is that my users can see the group list (those they have access to) but when they click on a group the browser directs them to a blank page (no fronted error).
The site seems to work fine with GroupJive 2.7.0 and this is how I have left it at the moment - In the admin areas CB complains about 2.7.0 being incompatible with the current version of CB but since it works....
Clearly something is out of kilter (I have had to actually delete every GroupJive module I am not using before it would even let me 'upgrade' (see my OP) - I have left only the core GJ plugin and the GJ file plugin installed and published). I will keep working on this and see if I can find out what the problem is since I am sure the incompatibility between CB core and GroupJive 2.7.0 will bite me at some point but at least I have an operational site at the moment so the pressure is off.
Many thanks for your help to date - if any possibility \ idea for the behaviour I am seeing comes to mind, please let me know.
Regards,
James.