I have been asked to create a visual which looks like the one below, I can best describe it as a stacked funnel or perhaps a centered stacked bar chart. I cannnot see it as an available visual in Power BI but am assured that the sample from which this has been drawn is indeed Power BI.
I would really appreciate any thoughts or advice, it would be great if I can deliver this as one of my first projects.
I don't think we can make visual looks like the picture your posted by power bi build-in visual. To achieve your requirement, you can search the custom visual from here: https://app.powerbi.com/visuals/
If there is not what you want, you could create your own custom visual if is an experienced web developer.