The reality is that having them written down isn't going to change anyone's mind or persuade them to do something different unfortunately. I wouldn't bother wasting your time printing them.Do you think it would help by printing off and carrying a copy of the NR Conditions of Travel and showing the relevant paragraph to the staff member? Also is there anything to stop you from recording the conversation on your phone to later use as evidence that you were denied the facility?
It's important to be careful to speak politely and to try to smile when you're speaking with the staff, and no matter what to avoid appearing to be angry, but I thought those went without saying so didn't specifically mention them.
You could covertly record the conversation if you really wanted to, but in practice it would be no use otherwise than as a memory aid for you. I personally wouldn't bother. Politely ask for something in writing once, if that is declined then it is declined.