Qualys does not appear to have an issue [1]. Testssh.sh [2] complains that they offer DES/IDEA and may also be vulnerable to CVE-2013-3587 but otherwise also gives them an A+.
Have you tried multiple browsers and is your OS CA store up to date?
Attackers might be trying to steal your information from www.gov.uk (for example, passwords, messages or credit cards). Learn more
NET::ERR_CERT_AUTHORITY_INVALID
Have you tried multiple browsers and is your OS CA store up to date?
[1] - https://www.ssllabs.com/ssltest/analyze.html?d=www.gov.uk
[2] - https://github.com/drwetter/testssl.sh