Hi paul.h
Just about to give up hope. So thank you for replying.
In my C2 case the Haynes Manuel gives very little information on servicing the gearbox as it supposed to be sealed for life, as a great believer in changing oil as part of a regular servicing rescheme weather it needs it or not, my OCD had to change the oil so I drained the oil. found on the internet it takes 2 litres to fill, I found the vent cap ( right hand side underneath the air filter, round and black which just pulls off. slowly poured in 2 ltr of gearbox oil. job done. something dis concerning about not having