“(3) Service of a bill shall be effected in accordance with Order 67 rule 2 at least 6 weeks before the day on which the bill is to be taxed.
“(4) A party on whom a bill is served may by notice object to any item in the bill.
“(4A) A notice under subrule (4) shall—
(a) list each item or part of an item which is objected to;
(b) state shortly but specifically the nature and ground of each objection;
(c) state the amount which it is contended should be taxed off; and
(d) be filed and served on the party entitled to costs and on any other interested party not later than 7 days before the day on which the bill is to be taxed.
“(4B) Subject to the discretion of the taxing officer to be exercised in exceptional circumstances, on the taxation of a bill no amount is to be taxed off, and no objection is to be allowed, unless the relevant amount is, or the relevant item, or relevant part of an item, and the relevant ground are (as the case requires) set out in a notice under subrule (4).
“(4C) The taxing officer has a discretion to—
(a) tax, or fix a lump sum in respect of, the costs of a notice under subrule (4) or of any objection; and
(b) add to, or deduct from, any sum payable by or to a party to the taxation those taxed costs or a part of those taxed costs, or that lump sum (as the case requires).”.