I had both of my Synthex's serviced and maintained by James Walker with no problems sourcing the bits I needed 'except' the case fan. That was replaceable but the new ones always gave a vibration/hum, even when using rubber mountings. In the end, I just put the noisy old one back in which was better than the vibration.
He also said at the time, that parts were good for at least another ten years..... That was about three years ago. I suspect they're still obtainable after that, just maybe harder to find like some other vintage synths I guess.
Buy it.... it's worth it.