well I've finally bitten the bullet and booked my V10 (SWB) in for a gearbox "service" at ZF in Dortmund Germany.
I have read many good things about Herr Sagert and his team, and, having spoken to him at great length today I am feeling very confident that my gearbox will return to the silky smooth unit it was when it left Dresden.
Herr Sagert informs me that his team are well versed with the Phaeton, and can turn the car around in about 4 hours.
The cost is €450 including transmission fluid (full change) and all parts used for regular service! The oil alone in the UK is approaching €300, plus parts plus labour!!! Plus these guys really know their stuff.
For the benefit of other owners Herr Sagert (remember this guy is the real article ZF employed senior tech) strongly recommends a transmission oil change every 120,000km or sooner!
I will post a follow up to my visit in due course