Yes, I see. ‘Booking Wis’ plugin requires the “Administrator” role for access to all its menu items. It is the real problem.

Quick workaround: modify ‘Booking Wis’ source code. I may do it for you in case you send me this plugin installation package (support [at-sign] role-editor.com

I will try to add the feature to replace menu capability which was set by plugin in order to resolve the similar issues. It may require a few days…
It could not help in case plugin author checks user rights not in the menu definitions only, but at his source code directly, like:

if (!current_user_can('administrator') {
    echo 'Not sufficient permissions!';