AEG SANTO Electronic Fridge 3350-7KA faults

Question

This unit is a big larder fridge and has served us well. It was not cheap!The unit has developed a fault and the green LED indicators continually flash.These LED's are what you use to set the temperature and monitor the settings when set-up. However, sometimes the unit goes in to cold operation run-away and has to be switched off and other times it fails to fire up.This all points to the thermostat failing or not operating as set.I'm willing to give a go at sorting the thermostat (if the fault is to do with that) but I can't find the thing!Any suggestions or advice?Many thanks,Gary