There's a safety sensor switch on the rear quarter panel (drivers side),
when the hard top / soft top is removed the rear window drops down into he door, the window can't activated by dash switch and rear wiper wont work either.
Undo the four clamps and re-position the soft top frame so it sits over/on top of the sensor
This....the hood isn't adjusted correctly.
The arm of the soft top has a small cam on the drivers side and this needs to press the little button (sensor) on the rear pillar drivers side for the rear window to work when the roof is closed. When its open the cam rotates away and releases the button to stop the window working. I guess its to prevent some numpty from closing the rear window when you are piling down the motorway with the hood open as I can see that not ending well.
Open your roof up and you should be able to see it. It's all adjustable. As a temporary fix to get out of trouble you can push a bit of plastic or folded up card between the two but I wouldn't recommend it as a permanent fix especially as it can be correctly fixed by 10-15 mins of adjusting. Once its set correctly you don't have to do it again but tape the cam in position if you take the hood off for winter. Nothings so annoying as getting the hood back on and realising the cam position has moved.
And CB40 trials, the Maestro on steroids!! I wonder if there are any of those prototype vehicles about still.