I pulled the DT swiss end caps out with molegrips. Scratched them a little, but they still seem functionally ok. Have you considered just using the DT swiss centerlock things instead of the Shimano ones? They use hollowtech BB tool to tighten around the outside instead.
I tried with some mini-molegrips earlier but they were too small. Managed to give my finger a good crushing instead. I think I'll get one of the DT lockings and get on to riding the thing.
Thanks @Howard, thanks @M_V.
The manual doesn't detail how to remove the disc. End caps/adapters need mounting in vice to remove though. Maybe it's time I bought a vice. Or one of these:
http://www.chainreactioncycles.com/dt-swiss-centre-lock-lock-ring/rp-prod10262?utm_source=awin&utm_medium=link&utm_campaign=generic205115&awc=2698_1457859505_94e0c6e75cedbbf066406226fff6c06e
Going to email DT Swiss and see what they say.