[ninjagull99]

Set PCM Settings to Stereo 2.0
Enable AC3 capable receiver
Enable AC3 Transcoding

Try this combination. Your TV should get Dolby for multi channel and should pass that.

Yes transcoding is really is the only option for Android Kodi legacy 5.1 audio Optical support.

As another note the Android TV (OS) has the worst Dolby Audio OS support vs FireTV and Apple TV’s.
Even devices like the Mi Box that supposedly have a Dolby Audio licence cannot for example downmix 5.1 DD+ > 5.1 DD and then send output over Optical.

Use Kodi instead. 

Many thanks for taking the time to post replies to me.  I sent the A95X F2 Android 9.0 TV BOX back and unable to test.  I still have my Nvidia shield, if I use the settings above is Mr Fritsch saying that My TV will pass the 5.1 surround sound signal to my Samsung surround sound system.  I read the thread on what box to get as a beginner especially for audio but there seems to be no mention of 5.1 over optical, only HDMI.  
Just wondered if anyone has got an Android box and getting 5.1 surround output from optical output?  Many thanks