I've just resolved this issue in my MY14.5 right-hand drive vehicle. The problem was a blocked aircon condensate drain soaking the passenger footwell, as well as passenger's feet, especially when accelerating or turning corners. There's the easy way, the harder way, and the hard but futile way. I've done all three (in reverse order).
First, the hard but futile way is to remove the wheel liner. On my vehicle, there is, as far as I could see, no drain in behind the wheel arch liner. So apart from cleaning out more crud than I expected to find, that was futile.
Next, the harder way, I removed the cover plate (3 Torx screws) and aircon duct in the footwell. There is a rubber duct at the bottom of the plenum chamber that appeared to pass through the firewall to the engine bay. Squeezing this didn't achieve much.
Finally, the easy way. With a cold engine, execution time- less than a minute. The outlet of the duct is way back and low on the firewall in the engine bay. The hardest part is finding it, as it's quite hard to see unless you know what and where to look for, but it's actually fairly easy to reach once found. In my case I simply had to lift up the rubber flap that covers the outlet (which is like a scupper valve for any nautical people). The flap must have stuck closed, and the second I lifted it with my finger, a gush of fresh water escaped. So satisfying.
I still reverted back to the "harder" method above and replaced the cabin air filter, which had been saturated, so exploration in that area wasn't wasted.
Photos of the outlet and flap in the engine bay are below. I'm pointing to it with a piece of yellow plastic in the second photo. Hope this helps.
