Its possible I have 1/2 resolved this - the network sharing was switched off on the Windows 10 machine, but now it comes up with a different error when finishing the installation - "the printer driver cannot connect to the network print server ..." . I have turned off the firewall and still the same message happens. BUT it says the printer is installed. When we try to print a test page from it everything seems ok, even with the firewall turned back on again, but printing real documents fails.
Any more ideas?