My CEL came on after about 100miles.
I disconnected the battery and about 100miles after that it came on again.
Since the CEL last came on I have been about 100miles and it is now OFF.

I wonder if the ECU has been able to 'retune' itself to within limits or something like that?
Maybe they had ECU's from different suppliers and only ones from certain suppliers are throwing the codes. May be a simple anomaly like that.