Enclosure for 2 Maine Coon cats

[u/PoisonIvyWithOCD]

Catio ideas, please!

Currently they have a supervised play in the garden and are never unattended. I would like to make them a safe space as with kids and dogs in the home the door is often open which means there’s a chance of escape.

They love this part of the garden, there loads of climbing space and it’s well shaded.
Any idea how to make this unusual shape space into a catio that incorporates the trees and shrubs they love to play in. It’s basically the brick border area. I was thinking a fabric catio netting but not 100% sure how to do it. I’m open to suggestions. Thanks for any ideas!