The truth of this matter is this, from the Guardian (as has been said already, no friend of Jeremy Corbyn):

"However, a Labour source said: “We have not been told that any member of staff has been refused a pass or any reasons for why any pass may not have yet been granted.”

With the process of completing the security checks for a pass sometimes taking many weeks and even months, some MPs concede privately that it is not unusual for staffers to start their job before a permanent pass has been issued."

So a non-story given undue prominence by tories and their fellow-travelers in the press.