Hello, well it seems now the checkbox on , don’t effect the landscape now seems to work, so you can now use the water body ocean on a height mapped landscape.
I also have now discovered how to remove the hole in the center they have by default for islands, this may be seen as a slight work around, but I found when I adjusted the splines to squeeze-up the hole the hole disappeared and there was no distortion in the water. It seems to work, so now we can use the water body ocean even if you have no island in the center.
The next issue however is the water height as I have not so far found away to raise the height to match the landscape water level, which I have posted here.