Hotpoint TDC30 only 1 of 4 elements working?

Hi... Hotpoint TDC30 tumble dryer, working at 25%.. three of the four elements do not get hot. All elements 'conduct electricity' i.e. are not broken/burnt out.. The single element is at the top and gets hotter when on high heat than of low heat indicating the thermostat control's working OK.
Wife's going ballistic, Any ideas before I splash out on a new machine?