So, I've now had a reply from the Department of Education who says that from all the evidence I provided them with, they agree that it was a retrospective consultation in contrary to statutory guidance. But as we "won" the Tribunal, my complaint has been resolved so there's no action Michael Gove can take. They've advised me that I need to continue my complaint through the LA process and then onto LGO. Basically, they are saying that the LA acted unlawfully but the Dept of Education is not interested because I got what I wanted via the Tribunal. So, the LA can break a law which is there to protect vulnerable children, but it doesn't matter one jot that they broke the law. 
I've now also had the 3rd stage response from the LA. It repeats the 2nd stage response - the LA is a snowy white shade of saintliness and the LA acted in littleTowie's "best interests" at all times. Yep, the official letter really did use the term my son's "best interests" [splutter]
Also, in my original 2nd stage complaint, I complained that the LA refused to engage with the Working Document prior to the Tribunal. In their answer to my 2nd stage complaint, the LA very arrogantly stated that there were X versions of the Working Document because all the many versions were a "direct attempt by all parties to negotiate before the hearing without the need for a full Tribunal'. In my reply to that, I took great pains in telling them that they needed to check their records, and if they did so they would find that Version 2 (ie the first version which the LA engaged in after I did the original version) was presented to the Tribunal minutes before the hearing and the Judge had to delay the hearing whilst my side read version 2. There LA did not attempt to negotiate at all prior to the Tribunal. The (many) other versions had to be amended post-Tribunal and were to correct the many many typos and incorrect markup formatting in the Working Document ("typos" or deliberate attempts by the LA to change the WD post-Tribunal?).
In the response to that, the LA have totally ignored the fact that they lied in their 2nd stage response. Then brush off their not engaging with the Working Document by stating that I could have gone to Parent Partnership or mediation at any stage. Really? So when the LA doesn't respond or engage in the Working Document, I should have gone to Parent Partnership or mediation to resolve it? 
My MP, initially reluctant to be involved, is now taking an active interest in developments and agrees that I have no alternative but to continue my complaint.
So, now I'm off to the LGO. But seeing other MNSNers' experience of the LGO, I'm not hopeful.
Anyone who has complained to the LGO got any advice they could share with me? What's the best process etc?
I am just gobsmacked that everyone I have written to says that I got what I wanted so I should just shut-up and go away.