I found a couple more interesting bits of info on the net for anyone who's interested in the cause of the Audi TFSI problem (as well as getting their engines fixed).
I found this about Audi's problems in the US...
http://www.topix.com/forum/autos/audi-a4/T532RVB94D9DR4EI0/p7
What I read here was that some cars in the US just had their piston rings replaced (as opposed to the rings, pistons and con rods in the UK). While this improved things in the short term, the problem of excess oil consumption quickly returned. What this says to me is there never was 'a dodgy batch' of of piston rings. The rings were just designed too thin (the objective being to minimise friction and maximise fuel economy). Thin rings give poor cylinder sealing, cause fuel to go into the oil and create circular problem that leads to catastrophic wear. I will lay a penny to a pinch of salt that Audi are now changing the pistons solely in order to use thicker rings to give better sealing.
The other thing I stumbled upon was this...
http://www.f150ecoboost.net/forum/4...sults-back-rx-catchcan-ecoboost-analysis.html
This shows the chemical analysis of something that someone collected in a 'catch pot' that they had fitted to their Ford Ecoboost engine. The Ecoboost is relevant here as like the TFSI, it's a turbocharged gasoline direct injection engine. The catch pot cools, condenses and traps the oil in the blow by gas that under normal circumstanses gets routed back to the intake system via the PCV valve. What the analysis confirms is that base oil is being 'distilled' out of the engine oil, almost certainly as a consequence of heavy fuel dilution. This is highly significant because it means the oil being routed in to the intake system has been divorced from all those chemicals that are specifically put into the oil (antioxidants etc) to prevent the base oil degrading. When this stuff hits a hot inlet valve, there is nothing to prevent the oil from decomposing into those nasty carbon deposits which so afflict the TFSI.
It's amazing what you can find out in cyberspace if you look hard enough!