Group Policy not showing ADM

Hi Experts,

I am fairly new to Group Policy, and I am creating a new GPO under a test OU containing test user accounts. My Domain Controller is running on Win Server 2008 R2.

I can see that, in the Default Doman Policy, I can browse to "User Configuration > Policies > Administrative Templates: policy definitions (ADMX files) retrieved from the central store >Classic Administrative Templates

But I have created another GPO in a child OU, and I am unable to browse down to 'Classic Administrative Templates' as this option is not there.

My goal is to 'prevent users from using registry editing tools' but I am struggling to find this; and obviously don't want to set this at 'Default Domain Policy' level, as this will affect Domain Administrators.

So I suppose there are two possible solutions out there for me, either learn how to get 'Classic Administrative Templates'  or if someone could tell me where to find the policy to restrict users accessing the registry editor.

Thanks