Where can I get a single din fascia for my double din b5; do i need one?

i have an Audi A4 2.4 SE Tip W plate (2000). At present I have a symphony head unit installed which, as you know is double din. I have bought an Alpine head unit as a replacement but am having some trouble understanding what is required also finding the parts necessary.

As i said the symphony is double din so as I understand it I need a fascia kit allowing me to install a new single din head unit. I have been to many car audio centres now and none of them have a compatible fascia. As I understand it I need a double din fascia between the years of 00 and 02?

To complicate matters i spoke to an Audi technician today who seemed to think it was just the side packing that I need and I have seen on some web sites reference to a cage that needs to be installed.

Any clarification and or help on parts supply would be much appreciated.

where you from? i have the single DIN from my 99.5 a4. we could exchange the cage.

Newbury in the UK. Sorry : <