Can't get 5.1 passthrough to work on Hifiberry Digi+

Hi, I’ve spent all day trying to get 5.1 passthrough to work with a Hifiberry Digi+ on a Raspberry Pi 2.
Tried with a 2015/10 OSMC image and a 2015/06 one.
Settings:
Hardware Support:
hifiberry-digi-overlay
everything below that disabled.
System:
Audio out: ALSA: Default (snd_rpi_hifiberry_digi S/PDIF)
Output config: best match
Limit sample rate: 48.0 tried 192 as well.
Stereo upmix: disabled
Resample quality: medium
Support 8 channel: disabled
Enable passthrough: enabled
Passthrough device: ALSA: Default (snd_rpi_hifiberry_digi S/PDIF)
AC3 capable: enabled
transcofing: disabled
DTS capable receiver: enabled

Tried with the spdif & coaxial but get no sound from movies with DD or DTS.
2 channel audio plays fine.

Also had an audio switcher plugin enabled on both builds but tried with it disabled and enabled but still no luck.

Any idea why it doesn’t work?

Cheers.

Finally got it working!
In video/acceleration settings MMAL needs to be enabled.
I had disabled it ages ago because I was getting video stutters after a while when using it. If the stutters start appearing again then the digi+ is useless for me and i’ve wasted £75 on the whole setup.