It nearly wasn't a quiet day but crisis averted. I was working on a document last night and thought I had saved it before Windows struck with one of their overnight updates.
To begin with, all I could find this morning was a copy from two days ago but, phew, inadvertently so, I had mis-filed it under a predecessor file and which had overwritten the text there. Therefore, as of now, I have them both back under their 'proper' files - I had a copy of that original file too in my email-send box to the client.