I think it works on two levels:
Establishing the relationship between Argentina and England. Che is the critic of all things "Peron" and he is pointing out that even in Argentina, the British are better. Also remember that on the Rainbow Tour Eva was not welcomed at Buckingham Palace, but one of the other palaces. Hence Evita saying: "Who the hell does the King of England think he is? Tea at some tinpot castle of his, what kind of invitation is that? Argentina deserves Buckingham Palace. If England can do without me, then Argentina can do without England."
On another level, Andrew Loyd Webber knew this would first premiere in England. I think it's a bit of fun with him pointing out the high qualities of his home England.
If anyone ever tells you that you put too much Parmesan cheese on your pasta, stop talking to them. You don't need that kind of negativity in your life.