@Graham_Gault currently there isn’t a two-way calendar sync option so that Outlook events will show within Asana. You’d have to rely on integrations like the one mentioned in this post: Outlook sync with Asana Projects and Tasks - #2 by Orin_Hutchings
While it would be great to achieve your ambitions within Asana, I’m currently using a third party integration tool called KosmoTime to centralize events and tasks across Asana and Outlook.