Okay, after another day of pulling up carpet and chasing cables I've finally managed to install the antenna, but only just. I gave up on the front bumper and decided to just mount the replacement on the spare tyre bracket, where the old one use to be. I didn't want to place it there for I've read it is not a particularly good location. While the previous areal worked fine the replacement is a lot shorter and cheaper than the old one and I'm concerned it might not work so well, but that's where it's at. It also turns out the new areal has a much shorter lead! I tells ya, that coax is like a bow string now. I accidentally plucked it during the install and it sounded an F
♯ 
Anyway, I got it all back together and replaced all the panels and stuffed all the carpet back and low and behold... I discovered spare bits
4 hex head screws and one of those mettle piece that clip onto the plastic to give the screws something to bite into. I'm pretty sure there from under the steering wheel somewhere but as to where I just can't see. I've now spent half the evening looking for a diagram to show where all the screws in the dash are meant to go, but alas, no such diagram was forth coming.
I'm pretty sure I have all the radio and centre flashing bolts in.
And I have these 6 in:
Anyone know where I can find a diagram that might help me find the others?
