Flashing main wash light Miele W838 washing machine?

From perusing many forums, I learnt that when the main wash light keeps on flashing this means there is a fault in the heating circuit. The manual says switch off and try again. Did that, same problem. Contacted Miele who said call out a technician. Well only as a last resort, so decided to take a look inside.

First thing I disconnected the machine from the mains. After opening the front (3 screws in detergent tray surround, 3 bolts around the door, emergency drain hose and the clip on the bottom left corner), I checked the resistance across the heater element: 25 ohms and also across the NTC: about 20k ohms at about 12°C. Took out the heater relay and checked it with 12v across the terminals: it worked. Checked the continuity of the leads from the mains supply board to the relay, relay to heater element, NTC to circuit board and circuit board to relay: all OK.

Started a 40°C wash cycle and added really hot water to the machine through the detergent tray as it started to fill. The main wash light stopped flashing.

So what's the conclusion? Problem on the circuit board? During a wash just before this problem started there was a huge unbalanced spin where a duvet cover swallowed all the other washing. Could this have caused something to fail on the PCB? Or maybe caused a crack in the soldering? I would like to take the PCB out to check it, but don't know how, so some advice on that would be gratefully received.