A:Answer Yes, this will solve that problem.
The Amazon Fire TV Stick HD supports BritBox, and it will work perfectly with your 2017 Samsung TV as long as the TV has an HDMI port (which it does). Just plug it in, connect to Wi-Fi, and download the BritBox app from the Appstore.
It’s a good solution if BritBox isn’t supported on your TV anymore, and you won’t need to replace the TV just for one app.