-Josh-
It's a Mk4. Might be the same but I've put it back on now.

The rubber seal comes off, so could be replaced.
-Jon-
Wasn't very difficult to remove the base. It' tells you in Haynes manual. Just remove the top part of the rubber seal around the boot, pull down plastic panel on roof (feels like you're gonna brake it), then pull down some of the roof lining, disconnect wire, undo nut and you're there!
The metal/plastic connector in the picture has a pin inside which (I guess) is meant to make a connection inside the other clip (in car). Upon poking some strands of wire down the hole it goes into, the pin doesn't appear long enough... So I packed a few (about 5) strands as far into hole as possible. This has helped to make a better connection. In some places my head unit will autotune to all the stations it should

, but it still isn't that great.
