So, in response to my own musings on easier ways of re-linking to the movie files, i found the following:

Quartz Composer Discoveries: “They're binary-format PList files. You can open them in the PList Editor tool, which also means you can save them out as XML. The reverse transformation is also possible, which means that dynamically creating .qtz files should be possible by writing out or transforming XML data, then converting to binary PList. The contents of the PList is just descriptive of the structure of your composition - nodes and connections - not of the rendered output or, seemingly, any compiled code (although there is a quantity of binary data in the .qtz file that could be some sort of bytecode). Could imply that .qtz files are really purely declarative programs - source-code, if you like.”

Very useful, so let's have a little play

So, to convert (thanks to the ever useful MacOSXHints.com) …

macosxhints - 10.4: Convert new plist files between XML and binary: "Apple has introduced a new .plist file format in 10.4. You'll notice that you can no longer just edit a .plist file in TextEdit or other text editors. The reason for this is that the files are now binary rather than raw XML.

"

And I can confirm that the plutil utility works as expected on the QTZ file (I changed the name from .qtz to .plist ; I don't know if it was necessary but there we go). And Having done that I could open the file in TextWrangler (which BTW is brilliant), and using the find function I was able to find all my linked movies etc.

I haven‘t yet tried the conversion the other way, but one thing I did realise is the huge importance of titling all your nodes (and perhaps putting useful information in the description) - it’s going to take some investigating to find exactly which node my broken movie was in (I need to decide whether to take it out completely).

Anyway, more later. SteamSHIFT out.