Hi Miles,
Creo View is not my specialty and I don't have the Express version available for testing but I have a couple suggestions.
In Creo View Lite, I found under the Home tab > Filters icon > then select the "Model Construction Geometry" items.
Also, take a look at the following document. You should do the opposite of the resolution since you are trying to show planes and the document is for hiding them.
https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS34808
If this doesn't work let us know as other users may be able to suggest alternatives.
