Hiding a ticket form on the 'submit a request' page

Hi!

I need to know how to hide a form from the 'submit a request' page drop down option, we don't want customers able to select it from the list (we are currently doing a trial by sending them a hyperlink to it through email contact). Customers are not required to sign in to submit a form so we can't use the option of hiding dependant on organisation (saw an article recommending this).

Does anyone know how I can do this please? Newbie coder here so not sure how to go around doing this!