What syntax is needed to make this work?

The 2.0 wiki recomendations don't work - I can see the inboxes or the folders but not both at once and there are lots of error messages about prefix clashes if I simply use the existing 2.0.20 conf file on 2.1.6

The layout I have is:

Inboxes in mbox format - /var/spool/mail/%u

Folders in maildir format - /var/spool/imap/%u/Maildir/

Control and index folders are under separate trees (/var/spool/control & /var/spool/indexes)

There's also a mbox area mainly for moving oversized inboxes (/var/spool/imap/%u/mbox/ - prefixed as OLD)

Presumably I'm not the only one who's had problems of this type?

Thanks in advance for any help Alan