Foreman 1.12-RC1 change Web UI certificate

I've installed Foreman 1.12 RC-1 and all is working OK, except when I try
to change the UI's SSL certificate from a self-signed cert to one signed by
my companies CA.

I have changed the following keys in the answers file:

server_ssl_cert New certificate signed by company CA
server_ssl_chain Corporate CA chain (includes root and intermediate)
server_ssl_key Private key for new certificate
puppet_ssl_ca Corporate CA chain (includes root and intermediate)

I than ran "foreman-installer", but this fails with:

Report processor failed: Could not send report to Foreman at
https://puppet02a.sysdev.zen.co.uk/api/reports: SSL_connect returned=1
errno=0 state=error: certificate verify failed

And any communication from the agents fail with an SSL error.

Executed an external process which logged to STDERR: Could not send facts
to Foreman: SSL_connect returned=1 errno=0 state=error: certificate verify
failed

The WEB UI is working OK and has the correct certificate.

Is there another key I need to change in the answers file, or a config file
that I have to edit ?

Thanks
Adrian