Thank you.
I re-established the power input to the oven selector switch and tried switching the oven on one setting at a time. All of the elements heated up when required by the selector switch. All of the warning lights came on as they should and so did the oven interior lamp. None of the settings tripped the RCD until the oven had heated up to the temperature setting on the dial. Could this still be caused by an element even though they all work? The thermostat tests ok. i.e. continuous until it clicks then open circuit.