note: A3's exits are not numbered. I've just checked them it with July 2023 GSV the other day. OSM is wrong here. I assume that the exits of the new section does also not have exit numbers.
I nearly put off doing it until tomorrow, then I found I hadn't used numbers and so wouldn't have to relabel a ton of points on top of extending the road.
I notice wegenwiki has added the exit numbers which, coupled with OSM having them, might have meant me relabelling waypoints - so thanks for the heads up, and busy work avoided!