4. If, and in so far as a provision of this Act operates, as and from the day appointed under section 1, in substitution for a provision of the repealed enactments, any order or regulation made or having effect as if made, and anything done or having effect as if done, under the substituted provision before that day is to be treated on and from that day as if it were an order or regulation made or a thing done under the provision of this Act which so operates.