First get the rubber seals off
whip the battery out- careful not damage scuttle panel and not to strain your back-its bloody heavy.
once out you will have the battery shelf nicely exposed- take it out too- its held by 3 bolts
once out you should be left with something like this
now you should be able to unblock passenger's side. just put your finger or stick or anything you like
through that blocked bung. now there is another one on driver's side. to get to it you need to remove alarm sounder (that round thing held in place by one bolt. you need to get your hand through and unblock that bung.i had about gallon of water sitting there
once all water is drained your plenum chamber should look like this
you can clean those bungs and put them back, personally i threw em away
then just put everything back
it is a very simple job and will help you prevent all sort of expensive issues related to water ingress
