On the taxation of costs to be borne by an estate or fund, the taxing officer may (a) direct which parties are to attend; and(b) direct the solicitor bringing in the bill to deliver or send to a client without charge (i) a copy of the bill, or any part of it; and(ii) any statement which the taxing officer may direct; and(iii) a letter informing the client that the bill of costs has been referred to the taxing officer for taxation and will be proceeded with at the time appointed by the taxing officer; and(c) if a direction is given under paragraph (b) , suspend the taxation for a reasonable time; and(d) disallow the costs of any party whose attendance is, in the taxing officer's opinion, unnecessary.