Here's an odd thing:
Std Xenons + lights in 'auto' + dayight = front Xenons on and rear lights on all the time as DRLs.
Std Xenons + LED rears (Byte 18 set to 04 as per StevePs guide) + lights in 'auto' + daylight = front Xenons and no rear lights...
Turn the lights to either sidelights or main lights and the rears come on.
Odd...but better!
I never understood why the rear lights were on as DRLs.
Glen