Daviesbike.
I had the problem you had and I fixed it quite easily. See 'Scuttle drains' thread in the bodywork section.
Take out your mats first. Dry them out and don't refit til after the cars stayed dry for a while.
Do the scuttle drain under the bonnet. Take off your tranny tunnel side trims and do those drain tubes either side.
(or maybe you've tried all this already??
)