[support] Viewing pages not yet published but need to be viewed

[Roger]

I'm very stuck on a fairly simple thing, can't seem to find a solution. 
Would greatly appreciate some help please.

I have a Views block displaying on a Content Type page "review page". It 
shows all not published pages - for review and publication by the reviewer.

I have a Rule that when the Reviewer logs in, the Rules -> Page 
Redirects to the "review page".
The review page shows list of page titles. All good so far.
When I as Reviewer click on a title I get error message, " Access Denied 
- Not Authorised to View this page"

I note in Permissions that there is no option to view unpublished content.
How can I grant permissions or access for the reviewer to inspect the 
content of each unpublished page?

Thanks in advance
Roger