I gather that it was the site of some flour mills years ago, and it has been done up to house a restaurant/café, and an outdoor eating area, some outside stalls, and they have a few pet animals as well. Nearby was a providore called Cheese, Meat and Salt.
Here are some photos of the Grounds of Alexandria.
Cover of the menu in the restaurant
The Doughnut cart
The lemonade cart
Beautiful white roses
The meats at Meat, Cheese and Salt
Lovely old door
A resident Macaw
Kevin Bacon, the pet pig, asleep in his house
Kevin Bacon with the other resident animals
We had lunch there and walked back through Sydney Park to the station and home. It was an enjoyable day out.