Usually green terror's will have a yellow stripe across tail and fins where blue acara seem to have more reddish....
The black stripe usually goes striaght through the eye of the blue acara and finish at the gill plate and blues usually have more of a blueish to the scales where green terror seems to be more of a greenish tinge,
Thank you everyone. I was not sure with the first picture as when I enlarged it I thought they had a green tinge, but the orangy/red on the dorsal fin confused me (easily done) Have mailed the chap see if I can pick one up.