Help needed Cleaning Lens elements on Canon 814 Auto Zoom Super 8 Camera

[Neale Langman]

Hi I am hoping someone can help. I have a Canon 814 Auto Zoom Super 8 Camera old one (not the electric version) and need to clean the lens elements. With my other Super 8 cameras it's easy to remove retaining ring to get at the elements but with this camera the ring will not budge. I can remove the outer casing easily enough but not get into the lens. I have seen people suggest tapping grooves with a screwdriver and hammer but that seems a good way to destroy the lens. I have tried my lens spanners and putting some acetone around the ring in case it was seized up but still no luck getting it off. Any advice would be appreciated. Thanks