Ok. I think I'll just leave it alone now.

SomeoneElse said that NP should display at some zoom levels but it wasn't doing that. I thought I was doing the right thing to make it show up in that way.
So is it possible to turn this back ? My understanding now is that I would identify existing ways and add NP data/feature to them.

Well I couldn't find a way of showing the extent of the NP so I thought it needed a single boundary. I hadn't got round to doing the coast. If woodland (for example) can be shown as a block why not a national Park?

Well I was just trying to create the full, continuous, boundary of the NP from west to east. The stuff I can see on this page doesn't mean anything to me. Why are some entries crossed out? for instance!