Welcome to the CPL Performance question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.
So, I suggest, for the exams, you adopt the protocol specified in ERSA.
However, what we normally do for performance work is look at the long section elevations of the runway and apportion slope segments sensibly to the analysis .. and then take the more conservative of the two approaches to cover ourselves from each angle (potential corporate/crew and legal liability).
I'm not familiar with the airfield but the ERSA information suggests that a TODA of 832m would be appropriate. If there were a RESA, I would expect the AD OPR to declare specific data. Alternatively, a pilot could enquire from the AD OPR for specific data over and above that included in ERSA.
Engineering specialist in aircraft performance and weight control.