Arse Monkey!
Still dead
EDIT: Going to bed - had enough. Seems to be that Outlook has a very screwy way of archiving files. I set a date for files to archive. Some files, some do not.
At least I have managed to push 100MB to my archive tonight to keep the SA off my back, but it seems if I try to archive a folder with many subfolders Outlook just throws all its toys out of the cot, and I have to go inside each one an perform an archive in there (and yes I have subfolders as well selected)