Waterleaks - Floorpan/footwells Focus 3 Door

Recently bought an 03 focus 3 door 1.6 (no aircon or sunroof)- it drove okay and smelt ok!!

Then it rained and both footwells filled up - car smelled of wet cabbage - garage removed l/h scuttle which wasn't "tight" to the windscreen and found the rubber grommet round the blower motor had disintigrated - replaced this and sealed with silicone - all dried out. Then it rained again and the car filled up with water again - garage said blocked drain holes on drivers side probably the culprit. Dried it all out, then it rained again and passengers side filled up again....gaffered up the scuttle on both sides to check where water was coming from, and dried the car again - no leaks altho it was a dry period of weather. It seemed okay, until I drove on a non rainy day but on wet roads (running out of fields due to being saturated) and hey presto both footwells full of water again :( ....dried it all out for the fourth time in 3 months..this is not looking good

- BUT strangely found that the bulkhead insulation was dry as was the carpet on the sills - it is only wet on the floorpan!!! had a good look and found a large plastic plug the size of a waffle (10cm x 10cm) in the floor pan where your heel would be and it was wet around the edges - had a look underneath the car and found water was being forced in through this "plug" by air pressure and as the plug has not been sealed at the factory, water was getting in when driving on a wet surface (had the same problem on a 1997 KA I owned) - have sealed this "plug" with sealant and gaffer tape on the inside and its still dry - so why do Ford have these plastic plugs in the floor - i've not had any of my other cars (Nissan/Skoda/Suzuki/Seat) with any waterleaks in the floor or stupid plastic plugs....bah - won't buy a Ford again...