I guess it might not be quite the same on the trad dash but I use a magnetic swivel mount from the base of the windscreen.
https://www.amazon.co.uk/Universal-Magne...t/dp/B00T0I54Q8I have fitted a case with the metal pad on it to the phone so I don't damage the handset itself. This clips to the metal swivel mount that is stuck to the windscreen. We used it for the complete trip around Europe and it did not come off.
The phone hangs down over the dash but obscures very little of the windscreen which is what I was after for obvious reasons.
The dashboard lip on the Aero is very short and so I am not certain how this will work on the Trad from your photo.
This is the mount and its location. The second image has the pad half way down the phone when it should actually be very near the top of the phone but it is a different one that I have with me today.


Would this work ?