Stuart123 Thanks for your post.
I'm in a similar situation with most posts here and have a VE Series II SV6 that has terrible FM radio reception.
Driving around Melbourne, and in particular, around the CBD, the FM reception is on and off, extremely static. Exactly like driving around listening to AM radio when you drive under the high voltage lines and get static. FM radio sounds exactly the same.
Watson Holden in Bundoora have looked at it many times under warranty, changed the antenna and base, checked the cabling... but the fault still persists. Many times it's that bad I just turn it off. Workshop manager has also been for a drive and heard the poor reception, but they continuously fail to locate the fault.
I'm reluctant to pull the dash apart to check behind as it still is under warranty (extended), but the inconvenience of booking it in, dicking around, inconveniencing my daily work, not having a car, to find they still can't locate the fault, is a real horses arse.