It's a very common misconception that the sending device makes any difference to Chromecast. The BT Sport app on Android app actually just acts as a remote control to send commands to the Chromecast - it doesn't matter how fast your mobile phone is.
The poor performance you're seeing on Chromecast has nothing to do with any Android app updates - the changes have all been made to the player appearing on your Chromecast. We've recently moved across to the latest player from Google, as the one we were using was years out of date and no longer supported.
We're still working with Google to identify the causes of issues on Chromecast, and fix them wherever possible.
We don't offer any way to launch Chromecast from the web player, and don't have any plans to do so. Even if we did, the experience on the Chromecast would be the same.
There are also no plans to offer a spoiler-free option to any of the large screen apps.
