(1) Section 811A of the Principal Act is amended -

(a) by inserting the following after subsection (1) -

 "(1A) Without prejudice to the generality of any provision of this section or section 811, sections 955(2) (a) and 956(1) (c), as construed together with section 950(2), shall not be construed as preventing an officer of the Revenue Commissioners from -

(a) making any enquiry, or

(b) taking any action,

at any time in connection with this section or section 811.

(1B) Where the Revenue Commissioners have received from, or on behalf of, a person, on or before the relevant date (within the meaning of subsection (3) (c)) a notification (referred to in subsections (3) and (6) as a 'protective notification') of full details of a transaction, then the Revenue Commissioners shall not form the opinion that the transaction is a tax avoidance transaction pursuant to subsections (2) and (4) of that section after the expiry of the period of 2 years commencing at -

(a) the relevant date, or

(b) if earlier, the date on which the notification was received by the Revenue Commissioners,

but this subsection shall not be construed as preventing an officer of the Revenue Commissioners from making any enquiry at any time in connection with this section or section 811.