Graeme explained on 11/06/2019 :
Problem is, the jet, which angles the water 90 degrees, is blocked. Managed
to clear a hole with a needle and very fine drill in pin vice, but not enough
to allow a jet of water through. A small drop comes through, but nothing
more. Unlikely to be scale as such, as this is a very soft water area. Any
thoughts on what I could soak the jet in, to help? Put through the
dishwasher last night, which softened the crud, and currently sitting in a
cup of hot water with a dash of washing powder. Vinegar, perhaps?

Remove the pipe from the jet and make sure there is good flow out of
the pipe. Sometimes there is a sort of jelly like substance which grows
in pipes, blocking jets. Easy way to clear them is with compressed are,
blown in from jet end of pipe, towards the bottle, making sure there
isn't a one way valve in the system.