[dugald]

Working from memory here.
Take a look at the antenna box in the trunk .... it should be obvious how it is mounted on its bracket and how you can remove it and extract the mast down and away.
Put some dish soap on the grommet to ease its insertion, rotate until it sits properly. Replace mast and antenna box.
Voila!

 

[Jeffrey Rupp]

Man, was that easy! I'm always hesitant to start disconnecting things I haven't messed with before. This was simple, less than five minutes start to finish. Many thanks.