Why does footwell keep flooding in Corsa 1.2?

Your heater is faulty time to replace it.

Each time you use the heater you're dripping radiator fluid onto your floor.

Alternatively you can go without a heater and join the two hoses that come from the radiator and poke into the firewall on the passenger's side (Australian Holden SB Barina Opel corsa 1.2 engine) these heater hoses are about 1" in diameter. I had the problem and used a brass plumber's hose joiner to join them works well in Summer :/