Magento – SOAP API not working over HTTPS

I have recently moved my site to run on HTTPS and have just discovered my stock update script is no longer functioning.

The script opens a SOAP API connection but the response i'm receiving is:

Fatal error: Uncaught SoapFault exception: [HTTP] Could not connect to host in /home/username/public_html/stockticker/processupdates.php:22 Stack trace: #0 [internal function]: SoapClient->__doRequest('<?xml version="...', 'https://www.kid...', 'urn:Mage_Api_Mo...', 1, 0) #1 /home/username/public_html/stockticker/processupdates.php(22): SoapClient->__call('login', Array) #2 /home/username/public_html/stockticker/processupdates.php(22): SoapClient->login('apiusername', 'apipassword') #3 {main} thrown in /home/username/public_html/stockticker/processupdates.php on line 22

I am using mod_rewrite to force everything to HTTPS, not sure if this might of had an impact?

RewriteCond %{HTTPS} !=on
RewriteRule ^.*$ https://%{SERVER_NAME}%{REQUEST_URI} [R=301,L]

and

Header add Strict-Transport-Security "max-age=84600; includeSubDomains"

Any idea's? I'm baffled and unfortunately this has a pretty big impact on my operations.

Thanks,