If your Passenger Number field on the search form is set to an unusually high number, or, you are unable to change it, this may be because the cookie that we use to remember the last options you made on the search form may be corrupt.
Clearing your cookies will reset the values that have been stored for the search forms and should correct this issue with the passenger number value.
You can follow the instructions in this article to discover how to clear cookies in your browser.