Coming Soon has revealed a little tidbit from Skyfall, pertaining to M as played by . The website was given access to archives of material and props made for the movie. Take a look:
There was also something else that cropped up while we were looking through the archive, something that may be of even more interest to Bond fans. As we looked at the porcelain bulldog M bequeaths Bond, the archive assistant read the inscription on the box it is presented to him in - "Olivia Mansfield bequeaths James Bond." We've searched around, and as far as we can see this is the first and only time anyone's ever revealed M's 'real name.' It may not have been spoken, but if you were watching on a big enough screen it could have been visible, so we'd argue it's now canon.
Very, very cool. M's name was revealed as Barbara Mawdsley during 's tenure, so it appears his M and 's M are two separate characters.
Like this revelation? Or did I just shatter your illusion that 'M' was for 'Mum'?