It was the engine side - where the slave cylinder is.
I can remember my yard showing me a standard VW slave cylinder they ordered and how it was ever-so-slightly different from the original where the tube connected. They were quite confident that they could adapt it, but since I didn't want to take any risk of having to open the clutch housing again, I told them to use the "Greenline-specific" part...which was specifically more expensive ;-( I'm only telling you this because, at least on my 2010 model, there was some small, but possibly important difference. So be sure to compare your old and new cylinders closely. Perhaps the cylinders were fully standardized by the time they got around to model year 2014.
Your Letrika manual makes me drool. I will send you a PM.
2010 Greenline 33' Hybrid
Home port: Malmö, SWEDEN
Currently in: Valletta, MALTA