The return spring on the rear wiper arm came off, I assime the whole arm needs replacing I am not sure how to remove it

Do I wiggle and pull or is there a retaining screw inside, if so how do I get the inside panel off

 

I worked it out
there is a plastic cap on top of the at the motor arm end you can lift this off by pulling apart the two sides
underneath is a small plastic cal which also includes the jet nozzles lift this off, be careful it is small and easy to loose.
Remove the nut and put some easing oil on the thread Partially screw back the nut - this is just to stop the arm flying off as you pull it.
The arm is on a spindle and will most likely be very tight.
Wobble and pull the arm until it comes away.
Warning
It is not recommended to try to force it by twisting a screw driver as that could slip and damage the window, but I did rest a pipe wrench on a cloth on the window around the spindle and then use the screw driver
I believe there is a proper tool but hardly worth it for a once only operation

Hope this helps someone

 

I have taken the cover off, taken the bolt off and no matter how much wd40 or wriggling I do I can't get the arm off. I was in the same situation where the springed bit had come off and was left with the last bit off the arm.

Is it literally just a case of getting that off or have missed something, do I have to do anything internally?

 

It was also tough but in my case '54 A3 it did come away in the end, of course you do need to undo the nut under the cowling they reccommend you loosen it rather than remove in case it all comes off quickly
I think I tried putting a collar undeneath, between the glass and the arm and tried to prize it up but I was worried about the glass but it may have helped