Gary here. Right, Lincoln Appliance NZ - thanks for taking the time to respond to my question. I appreciate that. The microswitch is working correctly both mechanically & electrically. And the polystyrene float is free to float.
It seems that I have managed to get this dishwasher operating again by discovering this; If you press the on/off button to on, then within a second press a program button, you see a number 13 in the display. Close the washer door and it goes through a cycle that lasts over an hour. Now, I can use the washer as intended, on different programmes. I think it's still early to make this a definite fix and I haven't read anything about a program 13 in the instructions manual.
Gary, March 2015