youtube-video-tabs
This is a simple Youtube tabs setup, no CMS — there are a fixed number of tabs each with a different video. A small snippet of code in the <body> section of the page settings stops the current video playing when any tab is clicked. Please don't ask me how to further customise the code as I don't know howwwwwwwwww
Thanks to @samliew and @weebhek for this solution.