Forget the CH interface, it only gives the basics.
Start by opening up an account on their site. Once done, telephone them and tell them you're looking for info on a Director with multiple appointments. You'll probably need to cite one example of a company the person is already a Director of, from what i recall they don't like to get into speculative name searches, but you might get lucky if it is an unusual name. Once pinpointed, they'll take your payment over the telephone, and email you a download link(s) or a simple company appointments list.
It works out a maybe a fiver or so, all depends upon how many companies that person is a Director of.