Last time it was used that I can remember was when they were doing engineering work on the points at South Gosforth. Trains were running Longbenton - Regent Centre using the avoider.
As for the Manors stock curve, don't think I've heard of this being used in passenger service. I did e-mail Nexus to see if they would consider using it when the Byker - Tynemouth section was closed but they wouldn't.