I can't remember what it looks like under there, but most have drainage holes at either end, sometimes its a flapped type hole, sometimes, just a hole.
If you need to get the scuttle, you'll need to remove the wiper arms, a few screw covers (plastic grommet type thing), then undo the screws.
To get the wiper arms off: Ensure the wipers are parked. Mark where the blades are at rest, either in the muck on the screen, or with tape. Lift the plastic caps on the arm pivot, undo and remove the nut (usually 13mm), i normally spray a little wd40 or similar on the splined shaft, so it soaks into the arms. Spray both sides and let the other side soak in.
Now lift the first arm up to where the spring holds it pointing up to the sky. Continue to apply a little pressure to the arm in the same direction, beyond where it wants to rest, then wiggle the arm from side to side. Normally they come off. Repeat on other arm. Note which arm came off which side.
Prise the plastic grommets off, undo the screws and the scuttle panels should pull up. Be aware there may be some wiring loom clipped to the scuttle panels, which you'll need to undo on the way off.
Refit in reverse, ensuring the scuttle is fitted correctly