Derwent Macdee rod stuck in system?

I have a Derwent Macdee cistern and the black rod that is attached to the C link has fallen in to the system and I can't get it back out.
The unit looks similar to the one displayed in Derwent Macdee's trouble shooting leaflet (http://www.macdee-systems.com/pdf/Troubleshooting-New.pdf) and was installed about 10 years ago. Can you please let me
know how to proceed?

Thanks in advance.