The Principal Act is amended -

(a) in section 811(1) -

(i) in paragraph (a) by substituting "In this section and section 811A -" for "In this section -", and

(ii) by inserting after paragraph (b) the following paragraph:

"(c) For the purposes of this section and section 811A, all appeals made under section 811(7) by, or on behalf of, a person against any matter or matters specified or described in the notice of opinion of the Revenue Commissioners that a transaction is a tax avoidance transaction, if they have not otherwise been so determined, shall be deemed to have been finally determined when -

(i) there is a written agreement, between that person and an officer of the Revenue Commissioners, that the notice of opinion is to stand or is to be amended in a particular manner,

(ii)

(I) the terms of such an agreement that was not made in writing have been confirmed by notice in writing given by the person to the officer of the Revenue Commissioners with whom the agreement was made, or by such officer to the person, and