Hi Grant - thanks for your input but I have done all the research including the Ringrip web site. They do not have these switches listed. There is a guy in Qld that sells heritage switches that include the plate, however these are Clipsal manufacture. I contacted Clipsal as well and although their switches look similar to the Ringrip ones, I don't know whether the locating holes are the same distance apart. Besides which they are @$23 each. I am really after the Ringrip ones.
Still looking - Bob