That is bad news but E30 windscreens are very very easy to replace. You should be able to pick up a 2nd hand screen for £20 and fit it quickly.

Between the windscreen wipers will be a clip which you can prize up and out with a thin blade screw driver. With that gone remove the black plastic trim that sit's inside the windscreen seal. Now you need to push the screen out, you can either do this from the inside with your feet or carefully from the outside fold the windscreen seal under the windscreen.

Good luck