Gearbox Issue - Service

[W12BTW]

Hi all,

i have problems with my A8 W12 2008 gearbox and hard shifting between 3rd-4th occasionally. Recently is much more prominent and started acting very weird like it doesn't know at what rpm to switch and rmp going up and down while traveling on gear. It feels like a software issue possibly due to some issue inside the gearbox. I have read a lot recently and having hard time to decide where to bring the car to be fixed. I live in London so any recommendation will be greatly appreciated.

Thanks
Jim