They are freeview hd channels and are available on the bt youview box at no extra cost.
Just press the red button when prompted to watch.
Vintage TV is available on Youview boxes . It is a service provided by Arqiva
Some but not all of Arqiva Connect channels are available on Youview boxes.
BBC red button and BBC connected red button are available on Youview.
All the above are available on Youview regardless of whether you have BT TV or not.
BT Sport connected red button is available at certain times for BT Sport subscribers on Youview.