Hi Dave, I apologise if I inadvertently deleted the way & its history.  I had split the way, deleted the jagged section, then went back and extended the ORIGINAL way with a higher level of precision.
I had no idea that iD editor would lose the history in this process, but retain the existing tagging !
I have checked the map this morning now its updated, and the By Brook is still complete. I don't think there was any info lost (other than creation & mod dates) so can we leave edit as is ?
I guess in the future, when a way is split and 2 are created, then its the one with the history intact that is the one that should be extended.
Live and learn, eh.
Cheers.