Try a native species, perhaps?

Both considered a bit over the top on the coast, but I was going to suggest either Pyrostegia venusta (orange flowers) or antignon leptopus (pink) Both vigorous but probably the first would be better as it's denser and more evergreen. And fast-growing.
Also possibly passionfruit vines - with the benefit of a crop?
Another option might be bougainvilleas but they would be slower growing initially and of course thorny.
Whatever you grow, consider giving it the benefit of planting a few at intervals and letting them fill in the gaps, and to avoid the waterlogging, plant them in a raised position, either in a mound, or in large planters with the bottoms cut out, or even in a mound made of a few tyres to get a lot of the root system above ground, then provide extra mulching.