I wont talk too much about the rest as im sure you know more than I, but keeping in mind there is free movement between NZ and Aus and that was stopped, hell, we had free movement between states in Aus stopped for a long time...sovereign nations surely have the right to protect their borders in extreme circumstances, and in the case of the UK...which is no longer in Europe and has a natural border...it does come across a bit like its just too hard
this bit though, Victoria during its second wave got to 700+ cases a day before it started to decline, and that was coming from zero cased for a long time, so you don't need to wait for the numbers to drop before to implement measures...the measures are what drops the number of new cases