I've found a way to download these DASH streams. Use Chrome, hit F12 to open the Developer Tools, switch to the Network tab and start playing the video, you should see the media start streaming. To obtain a copy, right click the media > Copy > Copy as PowerShell. Open a PowerShell window, paste the code into it and add to the end
-outfile c:\any\folder\location\filename.mp4
The file will be saved to the specified location with the specified name. It still won't work on encrypted media like Netflix but otherwise works around a lot of annoying players like JWPLAYER.