The Youview box has the Netflix player and that will play on your TV that you connect the Youview box to so you do not need a Netflix player on your TV.
Define "really old". What equipment connections does it have?
If it has HDMI then you'll be able to connect a YV box directly.
If it only has SCART then you'll need an HDMI-SCART converter. (Daughter 2 uses one to connect her laptop to a really old CRT TV in her flat).