[Retroman]

Maybe he did ask her plenty of questions, but we never got the chance to see.

Or simply had nothing to ask/ Pauline made it look like she wasn't allowed to answer lots of questions or didn't want to.

Or maybe he wanted to welcome the guest as much as possible and not fire questions at her endlessly, but instead show her a little respect.

I think he ranted about Carole because Carole was making it look like she distrusted Pauline and thought something was odd about her, and Brian thought it was unfair.

I really don't see how Brian not asking questions about Australia BB = fake.
He doesn't have to devote every waking moment of his life to being a Big Brother Fanatic, plus I think he was only a major fan of UK BB anyway.

Plus he may have only asked about Big Brother Australia on the phone out of general interest/politeness. It would have been the major talking point of the conversation to ask eachother how Big Brother is going.