No, we would be very quick. We can get a by-election going very quickly, and the Standing Orders were drafted quite carefully to give some freedom to the Speaker to abbreviate intervals. However, sure, you have to have time for people to agree to stand, because to stand as chair, you need a certain number of supporters and from more than one party.
If that did happen, the committee would not be completely helpless. These are scrutiny committees. They're not holding up legislation or anything. Their program might be briefly interrupted, but they can appoint a temporary chair at any time, and they do when the chair is away. Other people can take the chair, as happened this morning in your meeting.