TEKA LSE-1200S / HAIER HTD1268 washer/dryer – drying sensor?

Hi,
I have a TEKA LSE-1200S but it also looks identical to a HAIER HTD1268 washer/dryer.
Washer works fine but the dryer never completes – it times down to 10 minutes and then sticks at 10 minutes for literally hours (at least 2!). The washing is dry and very hot.

Even setting a dry cycle going with no washing continues for ever.
I’ve given the machine a good look over and can find no drying sensor anywhere. This is a condenser washer/dryer. I did find a 4 inch piece of thick walled pipe (about 4″ long, 3/4″ diam) loose but don’t see anywhere to put it so assume its just debris.

I would welcome suggestions on where the dryer sensor might be or what else might be wrong. I’m reasonably competent – I’ve replaced heater elements/sensors and drum bearings before and know which end of a DVM to hold but this one is driving me nuts – before I dismantle the whole darn thing can anyone give me a pointer?

TIA!
Paul