Although it relates to the initial test,
This document, published by the UK CAA may be of some guidance.
The "Departure" is a fundamental constituent of the test, so why you are surprised your friend was given a
Standard Instrument Departure with 5 minutes preparation time, I am not sure?
In the real world, it is not at all unusual for a departure to be changed at the last minute, and that shouldn't present any particular problems for a reasonably competent pilot.
I am sure you can refuse to do the test for whatever reason you see fit, but it could get quite expensive. You are expected to demonstrate proficiency to a reasonable standard. It is unlikely that the examiner is going to venture too far from the script, and you shouldn't be presenting yourself unless your general ability and knowledge is sufficient to accomplish all of the requirements of the test, whatever aspects the examiner selects for that particular day.