AT
I just wonder if you are tying yourself in knots and the best approach may just be to let her come in, do her thing, give her as little info as possible eg she has to rely on info from the useless TA and then pick holes in it with your team once you have the assessment
If she is in effect going to make up a load of old anyway, I would give her just enough rope to hang herself but be wary of giving any info about what you are working on privately / have put into effect as she may just rewrite her notes to claim credit for it
I know its hard to let these idiots access to your child, but on the positive side it means they will serve a report before tribunal telling you what their arguments are going to be and giving you time to come up with all the evidence which shows they are lying. You and your team can give oral evidence on the day remember.
I am worried you are going to burn out before the big day. I think you need to take a breather now so you can hit the ground when the last minute evidence comes in.
Do not lose sight of the fact your know this case and your DS a million times better than they do. And you have all the evidence which shows you have had to put private support in because she has not done her job and the current provision is not meeting need.
Great news the senior SALT got refused!
Top tip on tribunals (from someone who sits on the panel!) is to come up with a list of the 5 main points you want to get across on the day
Do not leave the room without saying those 5 things
There will be much you will not get to say and often lots of time wasting (by LA rep) goes on and loads of detail will not be discussed. So I think you need to not get too caught up in the detail but concentrate on ramming your main points home. You want to keep the emphasis on the key points and not let things go off track into debates about guidance etc, the Tribunal will just want to know 1.what your DS needs are, 2.what progress (or lack of) made and if this is adequate for his particular profile, 3. whether need being met currently, 4. if not are LA offering more, and if so will that meet need, 5. if not will your suggested provision meet need. Remember a Tribunal can use their own expertise and order something different to what either party have asked for.
His other top tip was that there are times when you should 'keep your powder dry' and not give too much away and I would personally not be giving her anything useful to work with, let her have to come up with something in a vacuum eg 'forget' the home school book that day, let any private SALT Notes not be available. She does not know your DS, that puts her at a huge disadvantage to your team and you certainly do not want to be filling in any gaps for her. Chances are the Tribunal will make her 'go first' when they are questioning witnesses so she cannot piggyback on anything your SALT may say.
They cannot actually fix the assessments - tests are tests and it would be rare for them to actually lie about the test results, however they will of course try and interpret them creatively.
Good to find out what tests they plan to do though so if those tests do not appear in the report you know they were not helpful to them.