Harry wrote:
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?