I can pass a Property value as a URL param when creating an instance

(User Story, To be Fixed , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Editor
Summary: Mainly to support setting isModel for Design a Model, but also hugely useful for creating child things.
For example, in the Lochleven space, we should be able to create a Component that points to its Item.
See comment: have found more-specific solutions to both of these immediate problems. We should find a general solution, but it's less time-critical.