Towards the end of the wash cycle the machine is supposed to flush conditioner (which we never use) from the soap dispenser tray into the machine. Recently though, the water seems to get pumped into the conditioner compartment faster than it is able to drain away – causing it to overflow. I can’t figure out whether the conditioner container has it’s own valve which perhaps is failing, or maybe it’s actually designed to overflow and drain into the soap chambers on either side.
Nevermind, I think I’ve probably found it. A piece of washing tablet plastic wrapper had somehow found it’s way to the back of the fabric conditioner compartment, hidden near the siphon. I’m guessing this was probably sufficient to partially restrict the flow, thereby causing the overflow.