Hi Dab, not sure. The dealer told me their electrician said it was a box that sent the current to the left side indicators and that it wasn't allowing enough current through. The box was to be reordered and was simply "plug and play". The module description was Morgans own description.
A friend has suggested it may well be a transistor in the black box that's at fault and that it ought to be fixable. That is of course just his surmising after our phone conversation.
Apologies, but electrics are a complete mystery to me. Does this sound like the flasher relay to you?