Huw and Ingrid's fixes

Hi,

There were many little fixes to do here in the works and copies screens.  Summary:

* Reordered many of the fields to be more logically arranged
* Prevent editing of catalogue linked data (and display a message why)
* Add access restrictions to show and edit screen on Works (they were on the Node object, not the Work, so I overlooked them before)
* Make editing the sub unit type a drop down box.

@terenceingram or @JonathanShaw these are mostly freemarker changes.  Can you please take a goosey and merge?

Huw.