I just tried talking to support about this issue but they were incredibly rude and unhelpful refusing to direct me to somebody that could actually help, disgraceful given my company pays for support. This never happened before Microsoft took over
So I bring the issue to the forums in the hope that a xamarin dev will see this and help me out of my struggle. The issues is as simple as the title makes out, I went to use the AVMetadataItem class for injecting metadata into a video however the class has simply not been implemented (well each property throws a not implemented exception). It is required to continue work on the project I am currently doing so it's costing a lot of resources until it's solved.
Hopefully somebody can help.