Missing tvmode hvfxsd

[RS]

According to modesref in the wiki, --tvmode=hvfxsd should give a 
resolution of 960 x 540 at 25 fps.

In the past few weeks I have found that an increasing number of 
programmes have fewer modes available, as reported by --info.  In 
particular --tvmode=hvfxsd is missing.  dvfxsd is still present, but it 
gives a frame rate of 50 fps rather than the expected 25 fps.  This is 
still the case with the latest version 3.28.

I came across these articles.

https://en.wikipedia.org/wiki/BBC_iPlayer

https://www.bbc.com/mediacentre/articles/2021/bbc-iplayer-new-look/

https://www.bbc.co.uk/iplayer/help/questions/recent-changes-to-iplayer/closure-oct-20

Does anyone know any more?