As for a change in the Anthem, Jerusalem was mentioned, the only problem I see with that is that it is named after a city that is not in the UK. Jerusalem is in Israel. That is like America using an Anthem named “Paris”. It seems odd to me.
‘Jerusalem’ the poem (set to music) isn’t literally about the actual city of Jerusalem, it’s about England.
In fact it’s specifically about Jerusalem not being in England 😄 It’s a warning about not being complacent and too nationalistic and it’s sung frequently by people who are complacently nationalistic.