(2)Notwithstanding anything contained in sub-section (1), if the notice of demand in the [* * *] [These words 'levy and' were deleted by Bombay 1 of 1940, section 5, read with Bombay 23 of 1948, section 2.] collection of the Urban Immovable Property tax has been served on any person before the coming into force of the Bombay Finance (Second Amendment) Act, 1939 (Bombay XVII of 1939), no sum shall be recovered as a penalty under sub-section (1) unless the person on whom such notice has been served wilfully fails to pay the amount of the tax due within a period of 15 days from the date of the coming into force of the said Act or within the period mentioned in the notice, whichever period expires later