Headless Chrome trust CA Cert - Linux

I have installed Google Chrome 63.0.3239.132 and am running some cucumber tests using the --headless flag, all is working fine until i am accessing a part of the suite that's needs the browser to trust our CA. At the moment i am just getting a blank page and upon further inspection i get this error

[0110/161130.895276:ERROR:cert_verify_proc_nss.cc(922)] CERT_PKIXVerifyCert for hendricks-js.localhost.test.co.uk failed err=-8181

So looking at various posts/blogs/docs it looks like there are two ways to get Chrome to trust the CA.

1) Use certutil and import the certificate to nssdb in .crt format

2) Add the cert to /usr/local/share/ca-certificates/ in .crt format and then run update-ca-certificates

Neither of these seem to be working for me, even though in both instances the cert is there.

Has anyone come across this with headless mode or know of anyway around this please

Thanks