What oil are VW dealers putting in your TDI engine?

[Transporter]

Would it be wise to do an oil and oil filter change at 7500km between services on a new TDI golf??

Not just the TDI, the TSI as well. I do it every 6 months (usually less than 7,500km) always before summer and before winter.

[Ryeman]

Transporter,
I'd like to do mine at 7.5k (with Penrite 5-30 Enviro+) but seem I'm up against the strictures of the fixed price servicing agreement.
Heard of a way round it?