c 5.6.3.2

I have admin access, I have created a new user group called "owner"
I have one user in that group "john"
I have one single page (reviews addon)
I have been able to allow john access to that page only, so he can approve or delete reviews.(he has to be logged in to do this)

However, i dont want him to see the top admin bar, as that currently allows him access to edit the page and add new pages etc.

My question ...
Is there a way i can hide that top admin bar when he is logged in???

Thanks