Displaying Notifications In Master-Detail App - No Error But No Notification Either

I'm trying to get notifications going in a Xamarin app, initially in the Android side, then I'll do the iOS. I downloaded the android sample app and it works just fine. However,

Solution 1:

So, upon further investigation and digging out older devices, it would appear that this is an Oreo issue.

It appears that the official documentation is lacking and the demo projects do not allow for Channels and this is where the problem lies. It has nothing to do with master-detail - my code works just fine (all versions) when run on an older device, just not on 8.0+ - now I just have to fix it.

Edit: based on the post by kylewhittington in this github thread (about the 8th post) I have now managed to code a solution which works in both Oreo and older version of Android. Just have to add the code for iOS.