2005 Vauxhall Corsa water getting in

i have exactly the same problem as yourself,i have removed the cars interior and carpets.the water is coming in from the pedal box area underneath the dashboard. it has been a nightmare to find out where the leak is.the car is going in tomorrow for an investigation report to find out why this is happening. i contacted vauxhall customer services on 08450 902044 and reported the problem,they gave me a case refernce number, that i then give to my local vauxhall dealership,the car goes in for investigation and they then discuss their findings with the main vauxhall customer service centre,this seems to be a common problem with corsa c's. but nobody has ever actually reported it to vauxhall, if it is easy to fix i will do it myself, and pass on the information that every corsa driver seems to need,The scuttle panel you refer to is the black air vent panel that sits along the bottom of the windscreen under the wiper arms.the passenger side is fairly easy to take off,it's just a couple of torx screws and sliding off the wiring harness that clips along the front edge, on the drivers side you will need to take the wiper arm off first before you can lift the panel off, i have already tried all the obvious things like blocked water ways and leaves underneath the panel etc, i;m afraid it's a bit bigger problem than that,,