Hi Roger..the code is 2670 .
Code 2670 is listed as an offense against Section 62(2) of the Police Powers and Responsibilities Act 2000 which relates to disobeying an instruction. The actual offense title is ' FAIL TO REMAIN AT A PLACE'..
Without casting aspersions here, can you be 100% certain that your son has told you the full sequence of events that took place... If he had become afraid or confused and moved off before the officer had completed his duties, that would explain the 2670 and subsequent fine amount..
There is no code for "behave inappropriately towards a police officer".... The nearest would be obstructing an officer in the performance of his/her duty