What do you mean by the 243 was a part of the original plan? Are you on about all 26 319s staying with Northern was part of the original plan? Something else?The 243 units was a part of the original fleet plan, which has changed since 2016.
I've not been keeping track of the 319s to be honest, so it's possible there's more which have been refurbished. However, they're all going off lease, with 319365 the second to leave the fleet.