To be purely flippant... they can be address in the May 2020 timetable (which has already passed D40 (9/8/2019) but at this point in time, again, it's a little too late to be thinking about undoing what has already, effectively, been done.
They have the ability to amend the entire timtable, each week, at STP timescales - but the work involved, initially would be tremendous. Once the 'amended plan' has been prepared and then validated by NR, it's a fairly easy job to copy paste for future weeks (still requiring NR validation though), so they won't like it -but would have to deal with it.
I would have thought that by now, Dec 19 work is dead and buried at NR, with shift of focus to May 2020 PDNS (Priority Date Notification was the 9th August) validation. It's really only diagram and minor variations on a periodic basis which will be happening at LTP level, fairly shortly, and the Dispute resolution process for the Dec 19 timetable taking place.