The online ordering is geoblocked,so I called Xemodex service and gave them my Visa details etc. Order was completed within 10 minutes and all documentation for Fedex emailed within 20 minutes. The documentation comes with very detailed instructions & a comprehensive Fault Symptoms Report. Cost so far is A$1 k. Faultless service so far.
Found this succint & clear explanation of the situation. Mine has gone into the limp home mode.
"There are two primary types of throttle position sensors (TPS): a potentiometer or a non-contact sensor Hall Effect sensor (magnetic device). A potentiometer is a satisfactory way for non-critical applications such as volume control on a radio, but as it has a wiper contact rubbing against a resistance element, dirt and wear between the wiper and the resistor can cause erratic readings. The more reliable solution is the magnetic coupling, which makes no physical contact, so will never be subject to failing by wear. This is an insidious failure as it may not provide any symptoms until there is total failure. All cars having a TPS have what is known as a 'limp-home-mode'. When the car goes into the limp-home-mode it is because the accelerator and engine control computer and the throttle are not talking to each other in a way that they can understand. The engine control computer shuts down the signal to the throttle position motor and a set of springs in the throttle set it to a fast idle, fast enough to get the transmission in gear but not so fast that driving may be dangerous."