Dumped oil out at around 21K and filled up with Mobil 1 0W40 - the only true fully synthetic oil I am told.
Could hear a very slight ticking at idle from one of the tappets for a while but then it went away. Have just had the car serviced at a main dealer and provided them with 5 litres or Mobil 1 to chuck in it.
Car now is the quietest it has ever been, especially on a cold start. KV6's are a little "vocal" when cold - slight piston slap from all 6 pots.
Mobil 1 is a truly fantastic oil and with the long intervals specced I imagine that by the time the engine hits 100K it will have been well worth running it on a fully synth that will not "gunge" up in places - eg the valve gear areas as I have seen on several engines run on semi synths!