It has taken me a while to realise this thread was going on, but now that I have found it, I just wanted you guys to know that Lucas wipers are the Englishmen's revenge for you guys' exporting things like "Oprah" to our TV stations.
BTW - the secret is in the switch. It is not a simple on/off affair. You have to use the correct Lucas part number switch (35927), which internally connects a live feed to the park feed , in the "park" position. A normal off/on/on switch just will not work for you.
Dia in next post might help, assuming you are using the right Lucas switch.