This message for Midgetace.  Thankyou for your help, and to let you know that one serious leak on my Skoda come from behind the pedals. You have explored that area, and found the offending leak. I decided to try to remove the panel which sits above the pedals. It has the diagnostics socket in there.

After removal of the torx screws, I mistakenly tried to prize it out. Panic ! The foam on the rear of this panel is sopping wet through. However, the panel would not come out, as I believe much more has to be removed first. 

I was going to check the wiring loom grommet as you described. Could you please advise on how to remove that bottom panel, which needs to come out to access the steering column etc. Look forward to your reply.

This might help - https://workshop-manuals.com/skoda/octavia-mk1/body/body_work/trim_noise_insulation/dash_panel/removing_and_installing_the_dash_panel_08.98_?/

Hi kentphil1

                     Thanks for the info and drawings. I am really hoping that I don't need to remove the steering wheel etc, just for the panel I mentioned. Maybe the lower dash with the lighting switch in it. I will explore later, but I expect there are more leaks than the one at the front. Always a damp car (windows running with condensation) Sound proofing can be squeezed like a sponge under the carpet.

Does your car have aftermarket door speakers fitted?.

 

If so, some people cut the plastic backing to let the speaker sit right, and this in turn is a point of water entry.

 

Also, if the sill drains are blocked, the the A post can fill with water and spill into the cabin area.

Where are the sill drains ? Thanks, I will check the plastic membrane for damage when I remove the door card.