I think like most Cosworth parts now they are no longer available from Ford. I managed to get my hands on one side complete, the arm, the blade and the washer jet and I paid iirc around £63 delivered. I sold it on eBay for £85 posted so by the time I posted it, eBay and PayPal had their fees/cut of it I was lucky if I earned a £10 note on it.
There was a seller on eBay a while ago selling just the washer jets for iirc about £40 a pair might be worth a search on there, other than that it’s a matter of sourcing second hand ones.