Well, to logout into tty and clean your kde icon-cache is something you might have to do if icons refuse to change outright.

gah! all good as soon as I posted this I found the actual icons!

After a long break from kde I am having a go at setting up my work machine with kubuntu.  I installed a flat look icon theme but there are a couple of icons I'm not keen on.  I have found the only files that I can see represent the icons in ~/.local/share/icons/FaenzaFlattr2-DarkBreeze  which is the theme i have chosen but changing by editing them in Inkscape seems to have no affect.   I have tried restarting and reapplying the icon theme.  Any ideas what I need to do?

issue replacing icons in kde