It is also available in the KXStudio repositories as an LV2 and as an internal plugin in falkTX’s ‘Carla’ plugin host. To use it in Carla you would need to add the ‘Carla-Rack’ LV2 or VST to a MIDI track and then load the internal ZynAddSubFX to the Rack.
Thanks for all your responses, I’ve just spent my $55 on zyn-fusion
All just for that magical trance sound mainly, and it seems to work just fine without going through the dependency hell which an earlier, free, version wanted me to go through.