Ronster said:

.... It also makes you wonder how much footage there is locked away somewhere.

There's loads of it we've never seen....and probably never will. But, these editdroid demo discs seem like a good source for this kind of material if anyone knows where to look........apparently each disc had different footage on it, so while ours contains takes from Luke and Yoda's conversation on Dagobah in ROTJ, other discs will have shots from completely different scenes on them. Keep your eyes open for any of these floating around, they're a potential gold mine for OT SW footage that you probably wouldn't get to see otherwise.