I'd let it grow a bunch more fans of leaves, Dom. These plants grow naturally in a crowded clump, sort of like daylilies, and I think they bloom better once they're crowded together. Birds of Paradise are the same way, won't bloom until they're crowded and comfy. Only thing I'd do is maybe add a handful or two of fresh potting soil around the bases - see where the rear one in your picture is putting out roots above the soil?
Here's a shot of mine. It was about 1/10th the size it is now when a friend gave it to me a couple of years ago. I just stuck it in a window box, and it has grown and expanded to this, pretty much unaided except for a little water in hot weather, and an occasional sprinkle of fertilizer. There must be at least 25 fans of leaves in this clump. I surely could divide it, but I figure I shouldn't mess with success. I took a picture of the base of this plant, but it was too dark and the camera wouldn't focus.
