[Wizzpop]

I had the same problem. Lifted the flap at the base of the wiper, removed the tube to the washer jet. The squirted WD40 in the tube in the shaft. Left it for a bit, then squirted more WD40. I had to take care to avoid the WD40 just squirting back over me. Left it a bit longer then operated the washer. A jet of white stuff erupted from the tube followed by clear water. There was no need to remove any panels to access the tubes and valves. Perhaps I was just lucky, but it's worth a try.