Vauxhall Vectra2001/2 Boot rattling and letting in water?

The boot lid doesn t lie flush with the surround but stands out proud allowing water to access + an annoying rattle as if the boot isn t closed but it is. I can stop the rattling by adjusting the 2 side adjusters out to maximum but this makes the lid stand up higher . I ve also adjusted the receiving metal pin as low as possible but it makes little difference.
Any suggestions would be appreciated