I've implemented the session test on the server.
There is certainly a problem so I've spoken to the hosting company about your suggestions. They claim it is working with all their other sites. Yet when I test using the above URL, clearly there still is a problem. The hosting company have sent me a php.ini file which I have attached. Not sure if they know what to look for.
Kindly have a look at the attached file and recommend changes as needed. Much appreciated.
Another problem I'm experiencing is that my product details page does not display on the live server. Yet on my local testing server it displays perfectly. Could this also be related to the above session issue?