Security review of our website and associated links

I need a security review of our website and associated links. Our website links through to a back office supplier where customers enter the details. We have had a number of emails from people using these links saying that they are not secure (SSL Certificates ) and I need a third-party review and report.

I need a quick call to start with just to run through the website and then a report that I can talk to our website /supplier if there are any issues

Thanks