Windshield washer jets: access & remove (2012 Estima Aeras)

[Kemlo100]

Problem: the washer jets only spray below the Wiper Blades and they are definitely not adjustable upwards.  The amount of water sprayed is good, but is aimed far too low  [Estima Aeras 2012 ACR50W 8-seat auto]

Each of the two small rectangular washer blocks has two jets.  They are fitted flush into the cowl panel that runs along underneath the windshield and wipers.  The problem I have is that I can't see how to remove the jets or even how to access the piping underneath them that feeds the jets. 

The end plan is to replace them with more standard, adjustable, protruding jets.  This will probably require me making a small rectangular support or filler piece that replaces the existing washer jets.  However, my basic issue at present is just getting access to the underside of the cowl panel that supports the washer jets.

Has anyone managed to remove or replace this type of rectangular jet?