9. These provisions, I consider, carry with them expressly or by necessary implication the power both to make directions and to unmake (that is, set aside) directions. If there is a power to set aside a direction there is nowhere, it seems, to draw a distinction, and have a logical stopping place, between directions which may be set aside and directions which may not. Further, as regards directions containing self-executing orders which have the effect of shutting a party out, it must also be borne in mind that under s98(1)(a) of the Act the Tribunal is bound by the rules of natural justice. The rules of natural justice require, in the first instance, that a party be given an opportunity to be heard. A party prevented from presenting its case could well complain that it was denied the opportunity to be heard. At the same time, however, a party which is persistently in default is not well placed to make such a complaint.