Tonight I thought I'd been jinxed by reading this article - the jet juice had run out today and the wife put more in

I got her to confirm exactly where she put the water, luckily it was the correct place, however the jets were no longer working.
(once when I asked her to check the oil level she filled it up to the top of the filler cap on the 156)
I saw the headlamp washers were working fine so water was getting through, just nothing from either windscreen nozzle, so I flushed the jets heads with neat screen solution and worked in with a brush - hey presto some action but not brill - repeated this 3 times and now she'll probably go through the whole tank in one day. Possibly she was dragging the dregs from the bottom of the tank which blocked the tiny holes in the jets.
Panic over