Please Help iPhone iOS 5.0 upwards: bluetooth disconnect and reconnect

Hi,

I have an RNS-E and audi car kit (S) model I believe in my 2005 A4. Since updating to iOS 5 on my iPhone 4, the phone disconnects and reconnects after a about a minute into a call. I've read various reports that Apple now uses Bluetooth 4.0 since the updates to iOS 5, which has mean't the older Audi car kits are the cause of the issue?

It looks as though the older car kits need a firmware update, and I wondered if anyone has updated using this firmware, or knows if any other firmware is available?

Software-Update > Mobile phone preparation (Bluetooth) > Mobile device database > Audi Worldwide

Looking at this, it appears to be for the newer telephone kits, but wondered if anyone had used it yet?

Cheers, Lee