Educational

thankyou all!
I did indeed make a minor mistake in that the flag I saw flying must have been Australian.
I spotted another one of these merchants in the Mediterrain CN25. This time I made a screen shot then compared it to a picture of the current Australian flag - they matched I had missed in the first encounter the additonal marking directly below the unionjack.
It makes sense but as the learned Cdre Gibs points out this is a post WW2 flag but the ship id book shows I guess the WW2 version in red?
Again my thanks for clearing this one up. Was worried something more sinister afoot - like a bad video card or driver corrupt.