Albert wrote:

I have an "archive back up" as well as an "Outlook back up" (*.pst
files). I have however lost my contacts (synchronizing with a phone
!!!) and would like to restore from these files. Upon opening these
files under "File, Open, Outlook data file", there is no reference to
a Contacts folder, only the folders relating to emails I have moved
to various categories I have set up.

I suspect you're viewing the PST with the Mail view of the Navigation Pane.
Switch to the Folder List view.
--
Brian Tillman