When Natalie Tate pays a visit to Cray at his home, she shows him key that she used to let herself in through the security door, presumably from when she lived with Cray. The key she shows him is clearly a square shaped key but when she places the same key down at the bar, it is definitely a different key.
When Clifford comes into the study to find Cray after he has won the election, he dismisses Nathan LaFleur - played by Michael Warren - by saying 'That will be all, Mike. You can leave us now.'