Dave Jobling - unfortunately I don't think a packaged workbook is going to help because of the stated "workaround". As Rick Clough noted it tends to be a random occurrence and if you close the workbook and open it back up it works fine - thus sending you a packaged workbook is in essence closing and reopening it (and thus no issue).
Rick Clough - I have also noticed that "saving" the workbook can do the trick to reset the issue.
Generally speaking it seems like the "refresh" button occasionally says "You already refreshed this session so we are going to ignore you". The only indication that it didn't run is that the process is faster and of course that the data doesn't change.
I am currently still using an old 9.3 version of desktop due to a different issue that is keeping us from updating - I'd be curious what version Rick Clough is on and if newer versions have fixed this.