Your DNS settings when you ran the command shown in your first post are different than the ones you have now.
For that request your apex name plumbingandelectrical.net.au pointed to a server at AWS. And, the TLS-ALPN challenge for that worked.
But, your www subdomain pointed to Cloudflare edge locations. This is because you had a CNAME for your www subdomain that does this
www.plumbingandelectrical.net.au. 10 IN CNAME wp.wpenginepowered.com.
Why do you point your www name to wpenginepowered? Did they give you these instructions?