In that case. you do not need to worry. There are 3 types of lottery. The one you are talking about is called a Small Lottery at an Exempt Entertainment. An exempt entertainment", whether limited to one day or extending to two or more days, means a:
bazaar, sale of work, f�te, other entertainment of a similar character. It does not matter if this takes place over more than one day.
The lottery must be incidental to the exempt entertainment, i.e. it must not be the only or the only substantial inducement to attend. The whole proceeds of the entertainment (including the proceeds of the lottery) must be devoted to purposes other than private gain, allowing for the following deductions:
1. the expenses of the entertainment, excluding expenses incurred in connection with the lottery;
2. the costs of printing the lottery tickets;
3. the cost of purchasing prizes, which must not exceed the specified sum (currently �250).
4. There must be no monetary prizes and tickets must only be sold or issued at the entertainment.
5. The result of the lottery must be declared at the entertainment.
If any of these conditions is contravened, every person concerned in the promotion or conduct of the lottery is guilty of an offence unless they prove that the contravention occurred without their consent or connivance and that they exercised all due diligence to prevent it.
The aspect of "five tickets for the price of four" applies to the more formal "Society Lottery"