New sites not cloning with default settings

Good Morning
I'm running a Multisite with the following plugins:
- Gravity Forms
- WPMU Dev Domain Mapping
- WPMU Dev Dashboard
- WPMU Dev New Blog Templates

I've created a main site:
I've then created a sub site:
This has all my pages, custom fields (via ACF Pro) and other settings in place (just dummy for now)

Now on my main site I've created a form (basic I know!)

I've not setup PayPal so I could get everything working. first

What should happen is when you register (and eventually pay) it will clone the master site ( which I've set as the default in Blog Templates

However, it's not doing this and just installing a basic Wordpress install

Have I missed a setting? Any help is very much appreciated as I'm new to Multisite!

Thanks in advanced