Replacing the stop-light fixed the leak into my 10 year old Aygo's boot. It's a shame I couldn't just buy a new gasket to replace the old perished one. But at least it was easy to fit.
Does exactly what it is meant to do, Bought this to replace the one I had, had for five years. it had eroded slightly on the seal, my boot was swimming in water from the bad rainfall we have had recently.
The new one stopped further leaking.