Behind the doorcard theres a see-through plastic weather sheet.

Would you remove this and sound deaden the inner skin?
Or should I take it off, sound deaden and then put it back on to stop the door cards getting wet?

I've already done the other skin with 2 sheets...

Remove it completely but make sure you sound deaden over all the holes it was covering.

Yeah this is what i'm doing at the moment, deadening over the holes. My 306 also had a plastic sheet which hung from the inner skin, over the back of the speakers, presumably to keep the water off them. I ripped this off with the rest of the door membrane but it's playing on my mind as the magnets of my speakers get a little wet now!

I put it back over the top of the deadening... It'd be rude not to.