Effective date of tax amendments clarifies staggered commencement, with most changes commencing later and select provisions deemed earlier. Amendments in the Third Schedule take effect from 1st April, 1969, except items 3 and 23 which are deemed to have come into effect from 1st April, 1968; this establishes a staggered commencement with most Schedule amendments commencing later and the two specified items treated as having earlier operative effect.