Anyway, back to the legalities. The reason for this apparent paradox is helpfully explained over at The Anglo Saxon Chronicle:
Lord Campbell-Savours was able to do this because he is protected from legal action for comments made in the House of Lords by Parliamentary Privilege.
That Privilege is granted to him in law by the provisions of the Bill of Rights 1689, which states: That the freedom of speech, and debates or proceedings in parliament, ought not to be impeached or questioned in any court or place out of parliament.
That's pretty clear wording.
Mr Chronicles has decided to go for the law with a full frontal approach: he's named the woman, as the Bill of Rights clearly says he is every bit as entitled to do as Lord Campbell-Savours, and is daring the authorities to prosecute him. It'll be interesting to see what happens. Good luck to him.
But I'm going for a slightly different approach: merely demonstrating that the law, even if enforced correctly, is useless on its own terms. I mean, look at this post. I haven't broken the law; I haven't named this bastard of a woman; and yet I have legally linked to Hansard, who have legally published the transcription of Lord Campbell-Savours legally naming her. This is ridiculous.