Pro Site permission upgrade issue

Hi,

When my users try to upgrade their site on my wordpress multsite using Pro Sites, it says 'Sorry, but it appears you are not an administrator for any sites.'. How can I make it so that they can upgrade?

I 'think' it is because I have not made them an Administrator but created a new role just with the permissions I wanted them to be able to do.
(User Role Editor plugin).
If this is the cause, any suggestions? (providing them Administrator access was giving too much functionality that I wanted)

much appreciated

graham