I have been in contact with the European Commission over the proposal I mentioned earlier. It would seem this is not a proposal for a piece of legislation after all, but a recommendation as to how EU Member States should implement the international instrument. That is to say, the drafters seek to influence, not control, the national legislation, and the various mechanisms for avoiding national parliamentary scrutiny will be unavailable.
I'm not going to retract my earlier comments, as the minutes of the meeting show people clearly contemplating that the Code of Conduct will be mandatory.
The UK Government ran a meeting last week about the proposals, and the Commission has said it will take into account such feedback as it received in its improperly brief consultation period.