IIRC the reserve is in the NSR panel in the boot
Remove CD changer if installed.
Remove screws of left luggage compartment trim and remove trim.
To fill, convertible top must be opened, actual oil level can only be determined when the roof is opened.
Remove oil filler plug.
Oil for convertible top hydraulics: G002 000 (same as power steering fluid).
Top off hydraulic oil only until oil level is between "Min" and "Max" marking.
Might help if you have a funnel or something similar to use
Screw oil filler plug back on tightly (5 Nm ).