(1) A person is an eligible person for the purposes of these Regulations in respect of a dwelling and a day in a prescribed year if—
(a) that dwelling is a qualifying dwelling;
(b) as regards that day he is liable (whether his liability is sole or joint and several) to pay council tax or council water charge in respect of the dwelling; and
(c) that day falls within a relevant period in respect of the dwelling.
(2) For the purposes of paragraph (1) above—
(a) a dwelling is a qualifying dwelling if—
(i) a local assessor has, after 11th January 1995, altered a valuation list so as to show as applicable to that dwelling from a date earlier than the date of making the alteration a valuation band which appears in the Table in section 74(2) of the Act below the band previously shown as applicable to the dwelling; and
(ii) that alteration has been made for a reason specified in sub-paragraph (b) or (d) of regulation 4(1) of the Alteration Regulations; and
(b) a relevant period in respect of a qualifying dwelling is the period beginning with the day from which the alteration by virtue of which the dwelling is a qualifying dwelling has effect (“the commencement day”) and ending with whichever is the earlier of—
(i) the last day of the month in which that alteration was made; and
(ii) the day immediately preceding the first day (subsequent to the commencement day) from which any alteration made for a reason specified in sub-paragraph (a) or (c) of regulation 4(1) of the Alteration Regulations has effect.