Can't help re the books for child, but just so your message doesn't go completely unanswered, thought I would reply.
Came off the Oceana 3 weeks ago - 12 day visit to the Med (& while glad not on her at the moment re the weather, wish I was still there in other respects), so if you have any questions just ask. If I can help I will.
This board doesn't have a specific place for P+O - I *think* they recommend using the Princess section, but I am not sure - never seen any comments re P+O there. Perhaps someone else can let us know!
The cruise critic and the P+O CruiseConnections (on the P+O main web site) have some people posting. There are also a couple of email based boards I read (WeLoveCruising and TheUnofficialPandOClub).
I haven't posted the web addresses as I can never remember which boards I am allowed to do so on and which not - but they should be visible through a search engine.
Hope some of this helps