Perfect, makes sense now. Thanks @Lurchzy and @J4MES OX4D.
I've now read that Sony seem to have still not made the game re-available in the 177 countries they are not in so even though PSN linking was made optional again, I don't think this is the end from a Sony perspective. I do think things can change in games over time, especially in live service ones like this one but clearly if they knew this before as an option that may happen then all they had to do was communicate it. Mental how many things fall over in the world just because someone didn't say something at the relevant time.