After a couple of hours in a heated underground all is well.
I checked that there was washer fluid.
Then I tried the wipers again. This time both jets sprayed easily. So it must have been something to do with our cold weather up here.
Relieved that it is working again. A little disappointed though that it would freeze up at only -10 C. I think my other car would have been OK with that temperature.
add some better quality fluid and a bit of alcohol to prevent frzg