Hi NeilM1234,
Thanks for contacting Apple Support Communities!
We understand that you're not seeing the options for Dolby Vision on your Sky Stream Puck using the Apple TV app.
If the content you're watching via the Apple TV app indicates that it is HDR content, it will play automatically so you don't need to make any adjustments within the app to play HDR content. You can learn more about how this feature works here: Find movies with 4K, HDR, Dolby Vision, or Dolby Atmos in the Apple TV app
"Here's what you need to watch the highest-quality video available
- Video content with a high-quality version that you purchased or rented.
- A device capable of playing high-quality video content:
- On tv.apple.com, you need a compatible device and display that can play the highest quality stream available:
- In Safari on a Mac with the latest version of macOS, compatible content may play in up to 4K HDR.
- In the latest version of Google Chrome, Mozilla Firefox, or Microsoft Edge on a Mac, Windows PC, or Android, compatible content will play in up to 1080p (HD).
- The latest versions of iOS or iPadOS, macOS, or tvOS.
- An Internet connection fast enough to watch high-quality content.
If you buy or rent a movie from the Apple TV app, you can stream it on the device that you bought it on and any of your other devices, as long as you're signed in to all of your devices with the same Apple ID. Learn what to do if you can't stream movies or TV shows. Your iPhone, iPad, iPod touch, Mac, PC, or Apple TV automatically play the best quality of video available for the device and your Internet connection.
If you purchase or rent a standard definition (SD) video, you can't play higher-quality versions."
We hope this helps.
Cheers!