While I'm posting up, I had an absolutely mind numbingly annoying rattle develop on the car.
I found it pretty much straight away with a bit of prodding. The tweeter on the passenger side was rattling about in the housing. Yep, drove me nuts.
Pulled the thing off:
Top tip, pull from the top. Get a fish slice or something similarly thin and plastic in there and when it's out enough fingers in and tug. There is a metal clip at the top that you want to free first and then the bottom sort of hinges on the two prongs and it then lifts off. Squeeze the top of the connector and the wiring comes off the tweeter.
How it looks separated.
The tweeter has three plastic springs push clips on it that clip onto the housing. On mine, they just didn't hold it tight enough to stop the tweeter moving in the housing. The driver's side seems fine.
Temporary fix, just to be sure it was the tweeter making the rattling noise.
Some thinly rolled blu-tac, just on the lip of the tweeter that makes contact with the housing.
Back together.
I used blu-tac because it is meant to be temporary as a test, and it will easily come off without leaving any residue if it wasn't. Suffice to say the rattle has gone.
Now I'm sure I've found what was causing the rattle, I'm going to whip it off again at the weekend and put some double sided adhesive tape on the tweeter lip instead of blu-tac. It's the stuff for mounting phone and tablet screens to bezels etc, very thin and super strong but not permanent should I ever need to remove the tweeter from the housing again.