If the BT you view boxes, including the new BT Pro box, had manual Freeview tuning then a lot of these problems would be solvable.
The majority of Freeview boxes/tuner allow you to tune into a specific 'channel' which maps to a specific mux. For some reason Youview never implemented this method and we have to accept what the box finds.
Manual tuning is an official way suggested by Freeview to sort reception issues, especially for those who get signals from multiple transmitters and who can end up with the wrong regional news etc.
https://www.freeview.co.uk/help/manual-retune