Is "early mark" only used in Australia and New Zealand?

What countries is "early mark" used in? It means being let out of something, typically school, early.

onelook.com only reports it being mentioned in Urban Dictionary, and it doesn't have information on what varieties of English use it.

Google ngram isn't very useful - too many uses of early mark without it having the meaning above.

Oz Words is even claiming that it's only used in some parts of Australia, while Superlinguo says its reach extends as far as New Zealand.

Is "early mark" only used in Australia and New Zealand?

I've never heard it in the UK, or from elsewhere.

Here's are three examples of how it's used, from Superlinguo:

• Goddam. The one day I am not writing on question time, the PM gives everyone an early mark. Why is life so immeasurably cruel and unjust?

• The net is down at work, but it doesn’t mean we can stop working or get an early mark… #fml #wtf

• Early mark for coffee today. I heard the inner call at 2.40pm

Searching for the phrase on Twitter Map ("See and visualize twitter users tweets overlayed on a map") only gives three positive results, all from Australia:

• 120dollarsfood from: Melbourne
  @iamevilcupcake Early mark.

• Mel452 from: Sydney, Australia
  Woot early mark. It's so dead at work. Going crazee!

• LyndonKeane from: St George, Queensland
  Due to a general lack of interest, I've decided to give myself an early mark.

Looking at early usage, an early mark was something that was earned in return for good results. Here's the October 2012 draft entry from the Australian National Dictionary Centre.

Here's some interdatings. First, from "From Our Mail Bag" in the Worker (Brisbane, Qld.), 26 May 1952:

Dear Uncle Toby,
I am sending a coloured picture for Ihe competition. I had a test on Friday and received 90 per cent, in dictation and 87 1/2 per cent, in sums. I also received an "'early" mark. It is raining down here. I have a poisoned foot. — Your unseen niece.
BEV. MILLS.

And in "Football Briefs" of the Barrier Miner (Broken Hill, NSW), 5 May 1954:

Central's schoolteacher forward Cec Fields has some fans already. Saw one little chap offer him a
chewing gum as he left the field at half time. Warrant an early mark, Cec?