Straighten
Randy W. Had suggested removing a door channel and making it straight.
I have not tried this but I have a similar project requiring the same.
I guessing that there is a similar channel out there somewhere. I was just looking at one of my hard tops the other day and I was wondering why they would put that little bitty Channel piece underneath the corner pad right on top of the drain holes in C pillar.
Below is a quote from a Fakebook posting. Might be pretty $ at a Land Rover dealer/
M. Clark The seal channel is the same on a Range Rover tail gate they come about 1 metre length try your Land Rover dealer