I also see 2 alternative ECS movements on RTT for an early Paddington departure on Monday, either from Old Oak or North Pole, plus I asked GWR help earlier if IET is confirmed for Monday and of course, they said no!
Of course they would say no. Plenty of times, again and again in fact, GWR are not giving any firm declarations as to Monday, because obviously, if all does go wrong, at least no firm commitments were made in the first place. It's not easy getting all these IET's signed off and approved for service by Monday, hence all the backup schedules for the ECS moves, but with any luck, all should form into place. Just a bit of a hiccup to overcome now, whereby GWR were hoping to use this weekend to get some last minute training done, unfortunately thanks to the no notice blockade at Reading, this won't be happening, which adds to the uncertainty. But there are definitely enough drivers, train managers and hosts ready to work the trains from Monday, so the only issue would be train related. (or maybe strike related reading what's been put up above...)