Radio Reception problem

[NickPicks]

I've just had the roof of my 2000 A6 Avant 2.4 SE AML resprayed, and now the radio reception is very poor.

So, the things I'm going to try are:

Check that the aerial is connected properly - they'll have disturbed that to paint it.
Check that the signal booster is powered (Is this part of the aerial? - it's the bee sting roof type)
Check that it's plugged into the radio properly (This means I'll need to pull the radio out, and I don't have the tools, but I expect this is least likely, as they won't have disturbed that to paint it)
Check the cable routing

So, a few questions:
Can I access the underside of the aerial mount through the rear courtesy light panel? (It's an Avant)
Is the signal booster integral to the aerial, or is it elsewhere (I read somewhere that there might be one next to the cd changer in the boot?)
Where is the cable routed? I presume it goes through the roof and down the driver's A pillar
Is the signal amplifier powered from the head unit? Does that wire run parallel to the co-ax signal cable?

I'll fish my manual out tonight and have a look, but I thought I'd ask for advice first.

I'm hoping that it's either the power or earth connection to the aerial / booster, and that I can get to it through the interior light unit. I hope it doesn't mean taking the head lining down.

[NickPicks]

I pulled out the light unit from the headlining, and the aerial cable isn't plugged into the aerial. I tried pushing it in, but it kept springing out, I think there's a plastic collar which keeps it clicked in, and that had split, so it went back to the dealer on Monday for them to fix it. The radio now works fine.

Now I just need to sort out the randomly clicking indicator relay, and it'll be fine.