The new tunnel was available for the new car development after the summer break -
https://www.mclaren.com/racing/formula- ... nd-tunnel/
Note this comment from the above link:
An old-specification McLaren model was used for the basic correlation of the wind tunnel ahead of the Summer Shutdown, which was the final stage of the process. Now complete, we notified the FIA that we would be leaving Toyota’s wind tunnel and moving into our new one. This is an important step in the evolution of McLaren Racing and the acceleration of our 2024 car design.
The recent interview in "The Race" with Otmar indicates that teams don't work on the new car until after the break -
https://www.the-race.com/formula-1/rena ... r-verdict/
Based on the above points, can the narrative in this thread from some posters that the 2024 car was designed with the old wind tunnel end? It wasn't.