Welcome to the Bunnings Workshop community @swindail.
It's fantastic to have you join us. Let me mention @raymao268 to see if they can answer your question for you.
There is the possibility that the kitchen was from Kaboodle as they offer a range of products which are suitable for undercover alfresco kitchens. Here's a helpful guide on what to consider. There is also a great modular range from Alfrescoplus to make building an outdoor kitchen super simple.
We look forward to hearing more about your outdoor kitchen project and encourage you to let us know if you have something to share with the community or need any assistance.
i have a concern because from the photo the existing floor drain was there to help remove excess water from back yard run off. now you have repurpose it the excess water will pool under your new deck.
I didn't actually cover the existing water drain, so the condition for water runoff shouldn't be changed. In fact, I made a removable cover for each floor drain, so it can be checked and cleaned if need to.