Hyundai Matrix / Lavita rainwater leak

Hi and thanks for reading.

My 2006 Matrix has a water leak pooling in the driver's side footwell. The garage has looked and said it is not the heater / aircon, not engine coolant (it froze the carpet last week when it was icy). They think it's rainwater. I've put cherry scented screenwash in just in case it's that, I'll be able to sniff it out. They've told me to investigate before bringing it back in.

I've checked the door and side window seals, and the drainage holes in the doors, nothing to see. The seals are soft and in excellent condition. There is no sunroof but there are roof bars. The garage has recommended I take it through a mechanised carwash to investigate further.

The only thing I can think of is that the drivers side indicator is a bit loose from the corner panel. Could that infiltrate in? Does the corner panel have drainage holes?

Does anyone know of any faults in this model or places where leaks have happened on yours?

Many thanks :)