electric multi-cooker (Knighton)

I would love to have something that is controlled by a thermostat so will cook at a precise temperature for a defined duration (unlike my slow cooker that just has power levels rather than accurate temperature control). As well as general cooking I'd want to use it to make yogurt (domestic yogurt makers only make 6 small cups at a time, I want to make about 3.5 litres at a time).