Fab PIP Tribunal News for CFS and some Questions

I was totally (and unnecessarily) petrified about appearing at my 16yr old son's PIP appeal tribunal last week. But he went from zero points in everything to higher rate care and low rate mobility which is quite an achievement for a claim of chronic fatigue syndrome. Thank youso much for all your help, and for the PIP guide booklets, without which I would have had no idea how to go about the whole thing.

I have a few questions please if you can help me.

The award is short (18 months) running from 1 November 2016 to 1 May 2018. I understand DWP routinely review PIP claims 12 months before the award end date, meaning if the DWP accepts the tribunal's decision, we will get a payment letter and probably on the same day a review pack (grrrrr) as review would technically be due 1 May 2017 just gone.

But I'm also pretty sure I've seen (maybe on here?) that there is a very small period of grace eg 6 weeks or 12 weeks or something, wherein DWP cannot require a fresh claim or review within a certain number of weeks of a tribunal. Is that correct?

My second question is what is the procedure to ensure that we do not have the same assessor next time? We have genuine grounds for complaint (full falsification of the PA4 and tape recorded evidence that this is what was done), but I don't really want to waste energy and time on a complaint, I just want to make sure we don't have the same person again. What do I need to do please? It was ATOS.