BTW I had a duh moment that lead to some out-of-focus shots with the Panasonic 20 mm pancake.
Even when everything is set to manual, if the power is cut to the lens (battery changes), the lens resets focus when the power is re-connected.
I notice that Panny is bringing out a newer model of this lens - not sure if this 'feature' is retained in the new model or not. I note that the newer lens' specifications no longer refer to a 'unique manual focus system'