A4 Avante multitronic gearbox rear mount 2003

[Sullydog]

hi
can someone help out please?
I have an avante 2003 a4. it has a little gremlin noise from underneath somewhere!
it sounds like a little click/clunk, it only appears when I reverse up my drive over the kerb.
I borrowed the use of an inspection pit and a good friend who pointed out that there seemed to be excessive movement in the rear gearbox mount.
So I intend to change it as a starting point, but I am confused as to what part number I need?
can anyone help with info and perhaps confirm my friends pointers please?

thanks