what oil was/are you using in the PD engines, as Ive found a couple brands which use 1/2 litre between services and then VW oil doesn't use anything 
Can't answer that one. I think its castrol?
Both cars were/are serviced by VW main dealer, a 105bhp Touran and a 115bhp Sharan.
The oil light on the touran used to come on between services, the Sharan doesn't use a drop between.
In my opinion, i think its extremely unlikely that any vw engine has an oil consumption problem.
Probably down to the oil used, or the individual engine.
Some use oil, some don't.