Well, there are oils formulated specifically for diesels such as Shell Rotella, Mobil Delvac, etc. But they're heavy duty oils meant for trucks, primemovers, marine diesels and generators. The lack of friction modifiers in these oils makes them a suitable alternative oil for motorbikes with shared sumps. Your BMW 320d is a fine piece of machinery for which BMW formulated the LL-04 standard, but since we don't use 4M particulate filters here, the LL-01 used by the petrol engines is the correct oil to use.
Don't be confused by gossip and hearsay.