Thanks. The sidebar entry has the blue folder icon and when I use it the tab and address bar have no icon.

I have changed the folder icon itself back to the non-system icon but changing it to the blue folder icon and the bookmarks star made no difference.

Can you please try moving the file ~/.kde4//share/apps/kfileplaces/bookmarks.xml somewhere else temporarily outside of KDE?

OK, thanks but then what ?

I moved that file to another (mounted) partition and launched the file manager. There is now a place entry labelled 'Home' which opens ~/ showing the icon both in the tab and the address bar. The file has been replaced.

Thanks for your patience and help. I will mark this as solved.

Sorry, I should have been more specific. I suspect that file had become corrupted in some form, preventing it from storing information on the icon for that location correctly.

Thanks. It was the word 'temporarily' which foxed me.