Just signed up to the forum to make a post about this issue (though our car is a Mk3) as I spent hours and hours trying to find someone else in the world with the problem, and then I've immediately seen this thread. 🤣 Everyone else seems to have had both washers not working (and/or the wiper motors not working); on ours the front washer works fine but there's no sound from the pump when trying to operate the rear. Fuse 22 was found to be blown so I thought replacing that might resolve it, but no joy. The other symptom we have is that the rear wiper runs constantly when the stalk is pushed back to the on position, whereas it seems it should be an intermittent sweep unless cleaning. So irrespective of the model, sounds like it's the stalk to blame.