Seems I have found the issue. Somehow theme-customizer set my selected themes "selected" option to Black so you couldn't see the selected item. Very odd as I haven't touched the colours. Diagnosed by switching to stock theme (blue) which worked then back to Digital nature (orange)
theme-customizer (0.9-82) stable; urgency=low . * only deal with transitions.ini in /usr/share/hildon-desktop * layout change color preset buttons in portrait * explicitly setting keep current wallpapers checked