AppleTV 4K and Apple Video Services.

I don't own a Mac, is there a Windows alternative to this?

No - you need to be running MacOS to be a developer for tvOS.

Just checking BGT on ITV Hub.

Commercials are 704x396 at 25fps bitrate of 1Mbs

Show ramped up from 704x396 very quickly to 1024x576 at 25fps 1.46Mbs h.264/avc video and 98kbs aac audio. (Whether that 1024x576 is sourced directly from 1920x1080 - and thus has detail up to 1024, or is a 702x576 scale to 1024x576 to keep square pixels, but with no detail above 702, I don't know)

Looks pretty similar to All4.

A far cry from iPlayer's 1280x720 at 50fps 4.6Mbs h.264/avc video and 128k aac audio.

The 50fps vs 25fps is crucial - it means iPlayer looks pretty much identical to watching Freeview/Freesat/Sky/Virgin, and ITV Hub, All4 (and Amazon Prime, Eurosport player etc.) all look sub-standard and second class.

Thank you for checking.

I found this trailer for AppleTV+.

Do you notice anything familiar broadcaster app icons in this picture.

AppleTV+ will support 4K HDR playback with HDR10 and Dolby Vision & Dolby Atmos sound.

So same as Amazon Prime and Netflix then. Anything less than HDR10 and/or Dolby Vision, and anything less than Dolby Atmos sound, would leave Apple TV+ as 'second rate' in comparison.

To be fair these characteristics have been available for sometime and are not new to this week’s announcements.

What are we looking for in particular? Lots of those icons are familiar.

Bit like SkyQ all nice looking but lacks HDR, HLG

Someone jumped the gun in the Apple Store this afternoon UK time and released to Series Link customers Cox's Planets episode three almost eight days early. I'm watching it now.