The issue was...
my session variable was an object.
For some reason the manager did not like a session variable that was a class object....
Solution:
1) output class object as an array and store that as a session variable.
2) on new page detect the class object was empty then check if the session variable was also empty.
- both empty then start new class object
- class object empty but session array contains data = feed session array into class to populate it.
Terminology may not be very correct but it worked.
Thanks to sottwell for her input.
regards