TDi oil is good advice, its full of detergents. Its also fine to use in the 1.8T. VWs own 504/507 oil is very good and contains all of the diesel detergents.
Interesting post, so what's a good aftermarket tdi oil to put in to try?
May try this on my lc for 500 miles then change for good synthetic.
I used the wyns engine flush in my engine last year when i changed the oil the big 40,000 mile service!!!
I use it every couple of years its not done any harm to my engines at all.
Worth a go in my opinion, only fast idle don't take it out for a drive or anything!!!