How do US networks manage with 50 different state governments?
Have a feeling this is ideological before anything else.
What's ideology got to do with it? It's just pointless to broadcast England only news to the nations, especially at a time when people need to be well informed about the rules and regulations they must follow in their nation. Having English only news presented first as the most important news is wrong for the nations where different rules apply and different governments are in charge.
A prime example of this was the Prime Minister's 10 May broadcast to the UK. Wales Today had to do a 30 minute program straight after it, telling viewers that NONE of what the PM had just announced applied to Wales and viewers in Wales needed to ignore everything they'd just heard. It was absolutely pointless the broadcast going out in Wales and Scotland.
Really do think your are trying mixing relevant to applicable.
It is just as important to know what the rules and regulations on Covid-19 on the other side of the border. It could be very relevant to a Welsh company who would need to know how they operate with being able to now move the stuff that they produce across the border.
Commuters would definitely need to know that public transport rules in England are now very different and can come with a hefty fine as the country opens up.
Applicable to the Welsh population? - No
Relevant? - Absolutely