Dom, I run a solenoid starter on my Gamine, 126 engine and gearbox, no problems with the exhaust. I use a push button to start and it works really well. I dont think you can buy new, not sure about the cc or sc as an alternative, but may be able to cut and shunt as stated above therefore I think you will need to keep looking on ebay to get one now unless someone has one lying about. Best of luck.
Ralph