Hi again, I'm sorry but i never looked at the link you posted and went straight into a reply. Now having looked (having read Dave Hill's reply) the varieties that I mentioned bear no resemblance to the african thorn acacia regarding the shape. Thats the bad news but the good news is that if your as mild as you say, then you could grow any of the varieties that I mentioned as even A. Baileyana will tolerate the odd night down to -5 o C. I'd go for the A. rhetinoides (the most lime tolerant) its quick growing, scented and unlike the others you get flushes of flower (very scented) during smmer and it flowers when young. It also, like several of the 'wattles' has two types of foliage, the young growth is similar to dealbata (small bipinnate leaves) which change to long strap-like linear shaped leaves (not unlike willow leaves but larger). Prune after the first spring flush and it will soon make a large bushy tree. Most Acacias do well near the sea especially on the south coast, so things are looking good for you ! One final point, dont be tempted to buy one thats too big and tease the roots out if they are seen to be going around the base of the container. Ideally plant one thats about 4ft- 5ft tall, give it only enough support to establish it, then it will be forced to make its own support root system (too big a stake will mean that they rely too much on it)
Hope this helps, Lannerman.