I've just discovered how out of date I am!
On reading Kwillmott's post I found myself thinking "That can't make sense. Anglia serves the area around Norwich, whereas Meridian serves the area around Southampton, so they obviously don't share a common boundary". However my brain seems to be stuck back in the days when Southern TV, and then TVS,
only broadcast to the area around the south coast:
https://upload.wikimedia.org/wikipedia/commons/8/85/TVS_1982-1992_locator_map.svg
I'd not realised that these days their successor, Meridian, actually covers a far wider area
https://www.itvmedia.co.uk/advertising-on-itv/regional-advertising
and does, indeed, share a boundary with the Anglia region.
So Kwillmott's post might well be relevant if Stargazer lives close to the Anglia/Meridian boundary (but clearly less so if Stargazer lives, say, on the North Norfolk coast). It certainly fits with the 20 October date for the changes on Sky and Freesat indicated here:
https://www.itv.com/news/meridian/2020-10-14/meridian-goes-hd-good-news-for-itv-meridian-satellite-viewers
If that's the case then the change to Meridian is probably both intentional and permanent but it will still be possible to watch the Anglia region content by using the 'extra channel' route that I've mentioned above.