A lottery shall not be unlawful if -
(a) it is promoted as part of a dance, concert or other like event and the persons arranging for the holding of the event derive no personal profit from the event or from the lottery, and
(b) the total value of the prizes in the lottery is not more than twenty-five pounds and, if more than one lottery is held, the total value of the prizes for the event is not more than twenty-five pounds.