Why is there a water leak in our Peugeot 107?

My elderly friend has a 2012 Peugeot 107 Active. It suffers from water ingress in the front passenger footwell. We have had it investigated by a local garage who have not cured it. Do you know what likely cause of leak please ?
You can fix this yourself with a teapot spout brush. The most common reason is blocked drains to the bulkhead ventilation well leaving rainwater nowhere to go except via the pollen filter into the car. The vent well is the well underneath the grille at the base of the windscreen. The drains are either side.
Answered by Honest John on

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