Update...
Took the car to the stealer, Camberley Audi (Colbornes), who tested it and declared it likely to be the Mechatronic unit. They suggested that the gearbox oil be changed, 1 year ahead of the normal maintenance schedule, and the "systems" reset as a precaution so we agreed to do this. We were charged £252 for the gearbox oil change service and asked to drive it for a while and see how it went.
The car is no different to the original symptoms described but to clarify, these symptoms were and continue to be intermittent. Some days it's perfect, some days it's jerky? Hot or cold doesn't seem to matter.
We fed this back to Camberley Audi and requested they put in a claim for assistance from Audi for the repair/replacement of the Mechatronic unit. Audi UK have replied to the stealer and rejected outright any claim for assistance. The service advisor at Camberley Audi told me this over the phone and advised that there will be no formal written communication to this effect. Do you think I should be offered written confirmation? Should I insist on it?
The car has just clicked over 12k miles, was purchased from new at Camberley Audi and has a full service history from them.
Camberley Audi have verbally provided an approximate price of £2K to replace the Mechatronic but cannot order the part without first checking our unit as, apparently, each unit is build for each car and have to be individually ordered. I very much doubt the latter and really don't have very much confidence in the Audi dealer system

So what to do? My plan is to write to the dealer principal if there is such a thing and possibly Audi UK, however I'm not expecting much joy.
Other than that we will continue to use the car as is until the problem either goes away or gets significantly worse and
needs to be repaired at which time I will probably take it to a specialist rather than put any more money in Camberley Audi/Audi UK's pocket.
Cheers
Mark