The service manager dropped off a Q5 (standard non-Sline) TDI 4.0 this evening - a decent thing to drive, feels no larger than the F3 Q3, and with a tank of fuel too.
We had a frank discussion over the original failure and I saw pictures of the shattered camshaft rockers - with the camshaft lobe ends literally snapped off, he suspects as do I, that there are still metal fragments somewhere in the engine, maybe visible to the naked eye or maybe not, I also got to see the flake of metal that is believed to have impaired the function of the valve actuator - there could be others that have not yet appeared.
The next step is to compare the idle characteristics with another F3 RS on Monday - which, of course, will idle smoothly because they all do - the next step will be getting Audi AG to authorise a replacement engine. I sincerely doubt that VAG have a replacement lump in stock so I'll be sticking miles on the Q5 for a while longer. If they don't, well there are still 3.5 years and 72,000 miles of Warranty cover remaining.

. Perhaps there is a lesson to be learned here - the warranty extension option to 5 years/90,000 miles is worth having?
With regard to being patient over the repair process, yeah I am.
I've stood where the Service Manager is (albeit 38+ years ago in a Ford dealer when the utterly evil Sierra, an escapee from R&D, had been dropped in our laps - Gromit will remember) and know all too well what it's like to have a stroppy driver demanding everything, it doesn't help one iota. The dealer didn't make the car, they are stuck in the middle between me and Audi UK/AG. It is more effective to be patient, let the process complete without pressure for anyone to make a hasty decision just to get rid of the irritating customer. The dealer staff have become advocates on my behalf, they want a satisfactory conclusion too. I didn't ask for the Q5, it was voluntarily offered with the observation that the A5s are low whilst a Q5 is another SUV - customer centric care.
Sure, its really annoying, but at the end of the day it's just a car - there are much more serious things in life to get worked up about.