Stop panicking!!
You've done no damage at all by what you've done, mondeo's/zetecs run very hot as std, but so long as stays within "norm" is perfectly ok, on a hot day like today, they can take a long time to cool, my dads is exactly the same, there isn't very much in the way of rad airflow on modern cars like mondy this is the reason.
I hope this puts your mind at rest don't lose sleep over it nothings wrong, just make sure you NEVER top the expansion tank to the brim like I've seen done, as that kills the head gaskets when it gets too hot and expands, or tries to!!
I keep the level on all cars to just above the min mark, that's fine.
tabetha