Front Panel removal HOOVER 500 automatic washing machine?

I have a washing machine HOOVER automatic 500, although its very old may be as old as 25 yrs. but it has so far given me a service which is unbelievably without fail.
Now recently i have noticed that front panel which has a door front loading has got rusted, now I wanted to open the panel.
The only thing which is hindering me , how to remove the rotory selector switch, I have removed the bazel of the switch, removed the hex nut in the centre slide the upper transparent free knob , but unable to remove the front upper panel as the rotory switch is obstructing to allow the panel to come out.
Once the upper panel will be out only then I have an access to the screws of panel which is to be repaired
Thank you
Please advise.