Code, which you showed above, should work for the users with right role. Let me know if you still have difficulties with it after checking a role ID.

It’s possible to use ‘ure_bulk_grant_roles’ filter. Return false with it to hide “Grant Roles” button. This is a quote from the URE source code:

 $bulk_grant_roles = apply_filters('ure_bulk_grant_roles', true);
 if ($bulk_grant_roles) {
     new URE_Grant_Roles();