Ended up measuring 135 x 53 cm, about 55mm tip rocker, and 50mm in the tail. (53" x 21", 2.1" tip and 1.9" tail rocker) I do expect it to loose a bit more of the rocker as the 12mm ply has only been soaked and the rocker bent in over a couple of days.
I was hoping to try it out today, but doesn't look like that will happen. Need to throw some wax on it first anyway. The rails are square, just been sanded lightly to remove the sharp edge. I've only finished it with varnish at this stage as i might change the rail shape a bit. I'll probably give it a coat with epoxy once i'm happy with it.