Where a billing authority has made a decision that section 47 of the Local Government Finance Act 198810 (discretionary relief) applies in relation to a hereditament and a chargeable day for a period, and that period includes days on or after 1st April 2012, that decision shall have effect from 1st April 2012 as if made under section 47 of the Local Government Finance Act 1988 as amended by section 69 of the Act.