Have seen it in other movies too.
Judy Dench as M has never been strong to me. Never sat right. I can imagine a female head of MI6, but just not her. The M in Living Daylights was spot on. Unfortunately it looks like they're building the whole plot round her character in this one.
Yeah, I would have much preferred Helen Mirren for Casino Royale, but it's sacrilegious to say so for some reason. If you can recall the other movies you've seen that plotline in I'd be interested to know. I'm a tad disappointed they're rehashing the M:I macguffin here, but I do love me some espionage shiz.