We have a PVC bay window. Recently it was cleaned on the outside and water appeared on the inside windowsill. It seems it had come in on the bottom of the window from the corner of the two frames. At the base, there is a plastic trim running along each window frame, But in the corners this sits away from the frame and leaves some voids that I wonder if they should be filled or sealed (see pics). Would anyone be able to advise if I should fill these? If so with what and how or if there is another suggestion?
Many thanks