I've never posted on any of these forums before, but I just wanted to let you (Flower) know that in the Fall 2011 application cycle I also sent in a personal statement to the Courtauld with a very obvious typo. One and a half months later, I was accepted to my first choice MA option. So, don't fret! At least in my case, one typo was not the difference between acceptance and rejection. You sound like you have a very strong professional and academic background, so I'm sure everything will turn out as it should. Good luck!