Those mowers are OLD. The generation of Kuhn that replaced them is getting to be of advanced age now.
One other option is to go directly to a Kuhn dealer. They might be able to help if they use their heads a little bit. I don't know if it's Kuhn that dropped support for that part or NewHolland... The main thing to consider from a parts standpoint is that not too many people are going to head to the dealer for cylinder parts. That's more generally a trek to a hydraulics shop anyway.