We've recently moved into a flat, the windows of which have large,
> protuding UPVC sills. When it rains, the noise of the droplets hitting
> the sill is so loud that we've twice retreated to the bedroom at the
> rear. As the sill is obviously hollow, would I be able to pump
> expanding foam in or, my favourite, cut the things off almost flush
> with the window frame and then close the resulting gap with section
> made from the removed sill? Any other suggestions/solutions?
Stick a solar panel over the head of the window - and then try claiming FIT for it!
Or you could try sticking a plastic head on the window - a man with you're range of knowledge should be able to do that with no problems (sarcasm intended)
As a matter of interest, why are you posting here and not uk.d-i-y - too ashamed to say that you've down-sized your property and had to leave the solar panels behind?