Hi

I want to do some market research for a potential busiess idea and I was thinking of having a competition on forums related to the idea. To enter the competition the respondent would have to answer a market research survey and they would then have to leave an email address and then they would have a chance to win a prize eg £50 iTunes voulchers.

My question is, to prevent just a few people responding and then me having to fork out £50, can I include in the small print that the prize will only be drawn if there are over 200 respondents?

Is this allowed or not?

Thanks

Charlie