Didn't know this existed! But want to do this so badly!!
Ok, so I didn't do this exactly, but mainly cos when I got there the thought of seeing a pic of myself flying behind a trolley just didn't appeal. I was also on a tight enough schedule as flight was only a few hours away and I needed to catch a Muggle train to airport! I did make a concerted effort to go to King's Cross and Platform 9 3/4 and it was brilliant and has inspired me to read HP all over again. I took photos of the platform so I'll post them below. To any Harry Potter fan, I recommend this little trip. And if there's no body-image issues, take the damn photo! :-)