Mr. Ullyatt, like any member of the public, could well engage in conduct of a kind that breaches the privileges of the committee. To take a totally unrelated example, if an individual were to accost any one of you on your way to Parliament and prevent you from getting there, they've breached the privileges of the House. You are entitled to have direct access to the House and to be unimpeded in your attempts to get to the House or a committee for the purposes of assisting or attending those proceedings. In that sense, a private citizen could well be guilty of conduct of a kind that causes a breach of privilege.
In the circumstances of this case, Mr. Ullyatt, as an employee of the member—as all employees—arguably is prima facie acting under the direction of his employer. That may not always be the case, but one might, as a starter, assume that. The employer is responsible for the behaviour of the employee, as arguably there's a vicarious responsibility on the part of the member for the conduct of the employee where that conduct gives rise to a breach of privilege.
Having said that, if the employee were acting without the authority of the member, the employee could well be found to be guilty, if I can use that term, of breach of privilege, in the judgment of this committee or the House, where his conduct is of a kind that frustrates the ability of the House and the committee to do its business.
The usual considerations that might apply to a member could well be applied to an individual employee, that what he or she has done frustrates the ability of members of this committee and the House to do their parliamentary business. That's a breach of privilege.