stuck lens cover HZ35W WB650

The four bladed automatic lens cover on my HZ35W seems to be gummed up and jams both opening and closing. When switched on the lens cover doesn't entirely retract, leaving a diagonal vignette. When switched off the lens cover sometimes stays open.

Does anyone know how to disassemble this part of the lens? I have a hunch that it requires a deep disassembly of the camera but if there's an easy solution then I might be able to get in there and clean up and lubricate.

For now my workaround is rapping the camera on something hard to dislodge the lens cover. That doesn't seem appropriate for a sensitive optical instrument