But you wouldn't say "screw the Queen," because you'd be British, see?
Yes, yes I would say that BECAUSE I'd be British 
What? Is it illegal to say that in the UK? Last time I checked there isnt any dictatorship or something in your country.
So yeah, it would be my moto.
Greece had a monarchy within the last century... And then the Communists tried to take over.
First of all, yes we did have a king, until after WWII.
Secondly, these communists you are talking about, were nothing more than powerful and wealthy people, who took over by force, by controlling the military. Basically, the whole military vs civilians.
And they werent communists, I have no idea who told you that. They followed the orders of a General named George Papadopoulos, who became a dictator very soon. What we had back then was dictatorship, NOT communism.
Lastly, these powerful people I mentioned, were actually Colonels, from many different regiments, joining one cause, to take over the country by force. This union was called Junta (Χούντα), and it went on after the war, so it crippled an already crippled country. Many of my people died from hunger during these 7 years, and some people would trade their houses for a sack of grain on extreme cases.
All this happened AFTER WWII (1967-1974).
Greece had a monarchy within the last century... And then the Communists tried to take over.
We fought and died for your monarchy damnit!
And then you got rid of them anyway. But you weren't Communists, that's for sure!
We did the job properly.
Unless you are talking about the pathetic attempt of the Communist groups to take over the country, by fighting with each other, causing a small scale civil war. WE got rid of them pretty quickly and easily, I may say, with the use of the military.
The Public just didnt want any kind of Communism.
Now, as far as I know, the British and the Americans supported our military (politically) in our fight vs the Communists.
Also, the military coup that Junta did in Greece in order to take over, did it following the original plan of a CIA agent that had infiltrated into the core of the existing government, 10 years earlier.
The plan was set into action once the CIA agent gave order (1967).
.....or so they say. This is not 100% confirmed, as the US government has denied any involvement in this military coup.
Anyway, our last King, Constantin the Second, (Κωνσταντινος Β') ruled from 1964 - 1973, and he was departed from Greece, from the existing dictators (Junta), thus ending monarchy in Greece.
Before Constantin the Second, we had some non-monarchy based governments, but thats another story. In short, in the period 1949-1974 Greece has changed more forms of government than I can count. Monarchy, Democracy, Communism, Dictatorship, you name it.
So, to answer directly to your comment, I dont consider that there ever were any communists in power, because they stayed for such a short period of time (less than a year), but technically, you can say that they were, and that we got rid of them.
Its....complicated, I'm only giving you the ultra-short version of all this, to get an idea 
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