Limit form submission to a certain number

We would use it when we’re booking training courses with only 10 places. Currently we have to watch submissions and manually switch the page over when we get 10. Apart from the obvious downside to this, we have to be careful how we word the page/form/confirmation email - we can’t confirm they have a place, we have to say ‘thanks for registering your interest’ - just in case we don’t switch the page in time.