Further developments.

I just made VPN connection to India and UK and I was able to access the site without a 503.  As soon as I returned back to a Australian (nbn) connection I receive a 503.

I have removed WordPress from the issue by placing phpinfo page there. 

http://tablelandfutsal.com.au/info.php

I can view the phpinfo from a VPN (from India), but not from Australia.  A plain html page works with or without a VPN.

I know the http GET request is not reaching the site as the phpinfo code is not getting executed from Australia.  

A traceroute is indicating the request is reaching Godaddy infrastructure in any case.

 

I have also confirmed the 503 is been generate from the site (198.71.233.141 -  tablelandfutsal.com.au) when attempting to execute phpinfo() command.  A normal html (no php module required) works.
 
Summary
Status: 503 Service Unavailable
Source: Network
 
Request Method: GET
Status Code: 304 Not Modified
Remote Address: 198.71.233.141:80
Referrer Policy: no-referrer-when-downgrade
 
When using a VPN from India the php works.  
 
Summary
Status: 200 OK
Source: Network
 
Note - other places around the world are also receiving 503.  
 
Therefore I believe there is an issue with the PHP module on my server. 
Maybe the php.conf is blocking certain subnets and returning 503 error.

 

How do I get this resolved as Godaddy support are saying it not their problem as they believe it is a server outside of there control.  The evidence does not indicate this.