I am not entirely sure what you asking? but you can change the fluid without actually servicing it. If your asking about the dealer service, they usually just change the fluid. Changing the filter isnt really necessary, its not hard either. After looking at my filter it was dirty but it didnt look detrimentally dirty.
My 2015 does NOT have a haldex. It has the "Active Driveline" and it is made by GKN, not Haldex. From what I have read, 2013 and earlier was either 2 wheel drive or a 4 wheel drive with a Haldex IV unit. So on those you want to change the filter and the fluid and there is a video online showing how to do this. In 2014 the Haldex was replaced by the GKN Driveline for the Active Driveline and the Standard Driveline...at least in the USA. I think in the UK many of the later models still had Haldex units.