^^ that was going to be my suggestion. If it is coming through the clutch mechanism. That should be sealed between the bulkhead and the pedal assembly. I do not have any further seals and do not get any leaks. (Other than standardnissue Land Rover) from The bulkhead.Is the rubber seal fitted and ok
There’s only one channel underneath the bonnet to direct the water out the side. If it’s coming in around the pedal heights that’s totally different. Are the mud shields still there? The bulkhead is protected by the mud shields and they have bolts though to the lower bulkhead foot wells to secure them.
Is it leaking whilst parked up? If it is the mud shields shouldn't be the problem, although worth putting washers between the bulkhead and the mud shield at some point.