The Ministry of Justice have now published detailed instructions for website operators who want to use the new Defamation Act 2013 process to handle allegations that third-party postings are defamatory. The instructions set out clearly what information needs to be in each of the communications sent and received by the website operator, and they seem to cover nearly all possible circumstances.
The only situation that UCISA and Janet pointed out that doesn’t seem to be covered is if a complainant repeats their complaint about the same posting before the process has been completed, either by the post being removed or by the complainant obtaining either a Norwich Pharmacal Order to force disclosure of the poster’s details. As far as I can see, the operator still needs to forward those repeat complaints to the poster, and the poster needs to repeat their response to the operator. But repeated complaints before a post is removed don’t count towards the “repeated publication” threshold so they can’t be used to force the operator to remove a posting more quickly.
The MoJ have also published a set of Frequently Asked Questions for Complainants, Operators and Posters.