A person who becomes liable to be registered by virtue of paragraph 1(1)(a) above shall notify the Commissioners of the liability within thirty days of the end of the relevant month.

The Commissioners shall register any such person (whether or not he so notifies them) with effect from the end of the month following the relevant month or from such earlier date as may be agreed between them and him.

In this paragraph “the relevant month", in relation to a person who becomes liable to be registered F3by virtue of paragraph 1(1)(a) above, means the month at the end of which he becomes liable to be F3so registered.