Thanks for your continued help with this.
I contacted my Host provider as there appear to be problems with passing authorisation information with servers that are CGI/FastCGI enabled.
They set up a script on my host as follows:
<?php$_h = getallheaders();print_r($_h);print_r($_SERVER);?>
I got this back from them after running that code:
[REDIRECT_STATUS] => 200
[REDIRECT_HANDLER] => hs-php55-script
[REDIRECT_HTTP_AUTHORIZATION] =>
And his comment was this:
"You can see the HTTP_AUTHORIZATION / AUTHORIZATION header is passed in $_SERVER['REDIRECT_HTTP_AUTHORIZATION'] due to the nature of FastCGI PHP required under shared hosting."
Does that mean that a different header has to be passed to the page?
JMB